{"Address.sol":{"content":"// SPDX-License-Identifier: MIT\n\npragma solidity ^0.6.2;\n\n/**\n * @dev Collection of functions related to the address type\n */\nlibrary Address {\n    /**\n     * @dev Returns true if `account` is a contract.\n     *\n     * [IMPORTANT]\n     * ====\n     * It is unsafe to assume that an address for which this function returns\n     * false is an externally-owned account (EOA) and not a contract.\n     *\n     * Among others, `isContract` will return false for the following\n     * types of addresses:\n     *\n     *  - an externally-owned account\n     *  - a contract in construction\n     *  - an address where a contract will be created\n     *  - an address where a contract lived, but was destroyed\n     * ====\n     */\n    function isContract(address account) internal view returns (bool) {\n        // This method relies in extcodesize, which returns 0 for contracts in\n        // construction, since the code is only stored at the end of the\n        // constructor execution.\n\n        uint256 size;\n        // solhint-disable-next-line no-inline-assembly\n        assembly { size := extcodesize(account) }\n        return size \u003e 0;\n    }\n\n    /**\n     * @dev Replacement for Solidity\u0027s `transfer`: sends `amount` wei to\n     * `recipient`, forwarding all available gas and reverting on errors.\n     *\n     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost\n     * of certain opcodes, possibly making contracts go over the 2300 gas limit\n     * imposed by `transfer`, making them unable to receive funds via\n     * `transfer`. {sendValue} removes this limitation.\n     *\n     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].\n     *\n     * IMPORTANT: because control is transferred to `recipient`, care must be\n     * taken to not create reentrancy vulnerabilities. Consider using\n     * {ReentrancyGuard} or the\n     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].\n     */\n    function sendValue(address payable recipient, uint256 amount) internal {\n        require(address(this).balance \u003e= amount, \"Address: insufficient balance\");\n\n        // solhint-disable-next-line avoid-low-level-calls, avoid-call-value\n        (bool success, ) = recipient.call{ value: amount }(\"\");\n        require(success, \"Address: unable to send value, recipient may have reverted\");\n    }\n\n    /**\n     * @dev Performs a Solidity function call using a low level `call`. A\n     * plain`call` is an unsafe replacement for a function call: use this\n     * function instead.\n     *\n     * If `target` reverts with a revert reason, it is bubbled up by this\n     * function (like regular Solidity function calls).\n     *\n     * Returns the raw returned data. To convert to the expected return value,\n     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].\n     *\n     * Requirements:\n     *\n     * - `target` must be a contract.\n     * - calling `target` with `data` must not revert.\n     *\n     * _Available since v3.1._\n     */\n    function functionCall(address target, bytes memory data) internal returns (bytes memory) {\n      return functionCall(target, data, \"Address: low-level call failed\");\n    }\n\n    /**\n     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with\n     * `errorMessage` as a fallback revert reason when `target` reverts.\n     *\n     * _Available since v3.1._\n     */\n    function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {\n        return _functionCallWithValue(target, data, 0, errorMessage);\n    }\n\n    /**\n     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],\n     * but also transferring `value` wei to `target`.\n     *\n     * Requirements:\n     *\n     * - the calling contract must have an ETH balance of at least `value`.\n     * - the called Solidity function must be `payable`.\n     *\n     * _Available since v3.1._\n     */\n    function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {\n        return functionCallWithValue(target, data, value, \"Address: low-level call with value failed\");\n    }\n\n    /**\n     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but\n     * with `errorMessage` as a fallback revert reason when `target` reverts.\n     *\n     * _Available since v3.1._\n     */\n    function functionCallWithValue(address target, bytes memory data, uint256 value, string memory errorMessage) internal returns (bytes memory) {\n        require(address(this).balance \u003e= value, \"Address: insufficient balance for call\");\n        return _functionCallWithValue(target, data, value, errorMessage);\n    }\n\n    function _functionCallWithValue(address target, bytes memory data, uint256 weiValue, string memory errorMessage) private returns (bytes memory) {\n        require(isContract(target), \"Address: call to non-contract\");\n\n        // solhint-disable-next-line avoid-low-level-calls\n        (bool success, bytes memory returndata) = target.call{ value: weiValue }(data);\n        if (success) {\n            return returndata;\n        } else {\n            // Look for revert reason and bubble it up if present\n            if (returndata.length \u003e 0) {\n                // The easiest way to bubble the revert reason is using memory via assembly\n\n                // solhint-disable-next-line no-inline-assembly\n                assembly {\n                    let returndata_size := mload(returndata)\n                    revert(add(32, returndata), returndata_size)\n                }\n            } else {\n                revert(errorMessage);\n            }\n        }\n    }\n}\n"},"Context.sol":{"content":"// SPDX-License-Identifier: MIT\n\npragma solidity ^0.6.0;\n\n/*\n * @dev Provides information about the current execution context, including the\n * sender of the transaction and its data. While these are generally available\n * via msg.sender and msg.data, they should not be accessed in such a direct\n * manner, since when dealing with GSN meta-transactions the account sending and\n * paying for execution may not be the actual sender (as far as an application\n * is concerned).\n *\n * This contract is only required for intermediate, library-like contracts.\n */\nabstract contract Context {\n    function _msgSender() internal view virtual returns (address payable) {\n        return msg.sender;\n    }\n\n    function _msgData() internal view virtual returns (bytes memory) {\n        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691\n        return msg.data;\n    }\n}\n"},"ERC20.sol":{"content":"// SPDX-License-Identifier: MIT\n\npragma solidity ^0.6.0;\n\nimport \"./Context.sol\";\nimport \"./IERC20.sol\";\nimport \"./SafeMath.sol\";\nimport \"./Address.sol\";\n\n/**\n * @dev Implementation of the {IERC20} interface.\n *\n * This implementation is agnostic to the way tokens are created. This means\n * that a supply mechanism has to be added in a derived contract using {_mint}.\n * For a generic mechanism see {ERC20PresetMinterPauser}.\n *\n * TIP: For a detailed writeup see our guide\n * https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226[How\n * to implement supply mechanisms].\n *\n * We have followed general OpenZeppelin guidelines: functions revert instead\n * of returning `false` on failure. This behavior is nonetheless conventional\n * and does not conflict with the expectations of ERC20 applications.\n *\n * Additionally, an {Approval} event is emitted on calls to {transferFrom}.\n * This allows applications to reconstruct the allowance for all accounts just\n * by listening to said events. Other implementations of the EIP may not emit\n * these events, as it isn\u0027t required by the specification.\n *\n * Finally, the non-standard {decreaseAllowance} and {increaseAllowance}\n * functions have been added to mitigate the well-known issues around setting\n * allowances. See {IERC20-approve}.\n */\ncontract ERC20 is Context, IERC20 {\n    using SafeMath for uint256;\n    using Address for address;\n\n    mapping (address =\u003e uint256) private _balances;\n\n    mapping (address =\u003e mapping (address =\u003e uint256)) private _allowances;\n\n    uint256 private _totalSupply;\n\n    string private _name;\n    string private _symbol;\n    uint8 private _decimals;\n\n    /**\n     * @dev Sets the values for {name} and {symbol}, initializes {decimals} with\n     * a default value of 18.\n     *\n     * To select a different value for {decimals}, use {_setupDecimals}.\n     *\n     * All three of these values are immutable: they can only be set once during\n     * construction.\n     */\n    constructor (string memory name, string memory symbol) public {\n        _name = name;\n        _symbol = symbol;\n        _decimals = 18;\n    }\n\n    /**\n     * @dev Returns the name of the token.\n     */\n    function name() public view returns (string memory) {\n        return _name;\n    }\n\n    /**\n     * @dev Returns the symbol of the token, usually a shorter version of the\n     * name.\n     */\n    function symbol() public view returns (string memory) {\n        return _symbol;\n    }\n\n    /**\n     * @dev Returns the number of decimals used to get its user representation.\n     * For example, if `decimals` equals `2`, a balance of `505` tokens should\n     * be displayed to a user as `5,05` (`505 / 10 ** 2`).\n     *\n     * Tokens usually opt for a value of 18, imitating the relationship between\n     * Ether and Wei. This is the value {ERC20} uses, unless {_setupDecimals} is\n     * called.\n     *\n     * NOTE: This information is only used for _display_ purposes: it in\n     * no way affects any of the arithmetic of the contract, including\n     * {IERC20-balanceOf} and {IERC20-transfer}.\n     */\n    function decimals() public view returns (uint8) {\n        return _decimals;\n    }\n\n    /**\n     * @dev See {IERC20-totalSupply}.\n     */\n    function totalSupply() public view override returns (uint256) {\n        return _totalSupply;\n    }\n\n    /**\n     * @dev See {IERC20-balanceOf}.\n     */\n    function balanceOf(address account) public view override returns (uint256) {\n        return _balances[account];\n    }\n\n    /**\n     * @dev See {IERC20-transfer}.\n     *\n     * Requirements:\n     *\n     * - `recipient` cannot be the zero address.\n     * - the caller must have a balance of at least `amount`.\n     */\n    function transfer(address recipient, uint256 amount) public virtual override returns (bool) {\n        _transfer(_msgSender(), recipient, amount);\n        return true;\n    }\n\n    /**\n     * @dev See {IERC20-allowance}.\n     */\n    function allowance(address owner, address spender) public view virtual override returns (uint256) {\n        return _allowances[owner][spender];\n    }\n\n    /**\n     * @dev See {IERC20-approve}.\n     *\n     * Requirements:\n     *\n     * - `spender` cannot be the zero address.\n     */\n    function approve(address spender, uint256 amount) public virtual override returns (bool) {\n        _approve(_msgSender(), spender, amount);\n        return true;\n    }\n\n    /**\n     * @dev See {IERC20-transferFrom}.\n     *\n     * Emits an {Approval} event indicating the updated allowance. This is not\n     * required by the EIP. See the note at the beginning of {ERC20};\n     *\n     * Requirements:\n     * - `sender` and `recipient` cannot be the zero address.\n     * - `sender` must have a balance of at least `amount`.\n     * - the caller must have allowance for ``sender``\u0027s tokens of at least\n     * `amount`.\n     */\n    function transferFrom(address sender, address recipient, uint256 amount) public virtual override returns (bool) {\n        _transfer(sender, recipient, amount);\n        _approve(sender, _msgSender(), _allowances[sender][_msgSender()].sub(amount, \"ERC20: transfer amount exceeds allowance\"));\n        return true;\n    }\n\n    /**\n     * @dev Atomically increases the allowance granted to `spender` by the caller.\n     *\n     * This is an alternative to {approve} that can be used as a mitigation for\n     * problems described in {IERC20-approve}.\n     *\n     * Emits an {Approval} event indicating the updated allowance.\n     *\n     * Requirements:\n     *\n     * - `spender` cannot be the zero address.\n     */\n    function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {\n        _approve(_msgSender(), spender, _allowances[_msgSender()][spender].add(addedValue));\n        return true;\n    }\n\n    /**\n     * @dev Atomically decreases the allowance granted to `spender` by the caller.\n     *\n     * This is an alternative to {approve} that can be used as a mitigation for\n     * problems described in {IERC20-approve}.\n     *\n     * Emits an {Approval} event indicating the updated allowance.\n     *\n     * Requirements:\n     *\n     * - `spender` cannot be the zero address.\n     * - `spender` must have allowance for the caller of at least\n     * `subtractedValue`.\n     */\n    function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {\n        _approve(_msgSender(), spender, _allowances[_msgSender()][spender].sub(subtractedValue, \"ERC20: decreased allowance below zero\"));\n        return true;\n    }\n\n    /**\n     * @dev Moves tokens `amount` from `sender` to `recipient`.\n     *\n     * This is internal function is equivalent to {transfer}, and can be used to\n     * e.g. implement automatic token fees, slashing mechanisms, etc.\n     *\n     * Emits a {Transfer} event.\n     *\n     * Requirements:\n     *\n     * - `sender` cannot be the zero address.\n     * - `recipient` cannot be the zero address.\n     * - `sender` must have a balance of at least `amount`.\n     */\n    function _transfer(address sender, address recipient, uint256 amount) internal virtual {\n        require(sender != address(0), \"ERC20: transfer from the zero address\");\n        require(recipient != address(0), \"ERC20: transfer to the zero address\");\n\n        _beforeTokenTransfer(sender, recipient, amount);\n\n        _balances[sender] = _balances[sender].sub(amount, \"ERC20: transfer amount exceeds balance\");\n        _balances[recipient] = _balances[recipient].add(amount);\n        emit Transfer(sender, recipient, amount);\n    }\n\n    /** @dev Creates `amount` tokens and assigns them to `account`, increasing\n     * the total supply.\n     *\n     * Emits a {Transfer} event with `from` set to the zero address.\n     *\n     * Requirements\n     *\n     * - `to` cannot be the zero address.\n     */\n    function _mint(address account, uint256 amount) internal virtual {\n        require(account != address(0), \"ERC20: mint to the zero address\");\n\n        _beforeTokenTransfer(address(0), account, amount);\n\n        _totalSupply = _totalSupply.add(amount);\n        _balances[account] = _balances[account].add(amount);\n        emit Transfer(address(0), account, amount);\n    }\n\n    /**\n     * @dev Destroys `amount` tokens from `account`, reducing the\n     * total supply.\n     *\n     * Emits a {Transfer} event with `to` set to the zero address.\n     *\n     * Requirements\n     *\n     * - `account` cannot be the zero address.\n     * - `account` must have at least `amount` tokens.\n     */\n    function _burn(address account, uint256 amount) internal virtual {\n        require(account != address(0), \"ERC20: burn from the zero address\");\n\n        _beforeTokenTransfer(account, address(0), amount);\n\n        _balances[account] = _balances[account].sub(amount, \"ERC20: burn amount exceeds balance\");\n        _totalSupply = _totalSupply.sub(amount);\n        emit Transfer(account, address(0), amount);\n    }\n\n    /**\n     * @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.\n     *\n     * This internal function is equivalent to `approve`, and can be used to\n     * e.g. set automatic allowances for certain subsystems, etc.\n     *\n     * Emits an {Approval} event.\n     *\n     * Requirements:\n     *\n     * - `owner` cannot be the zero address.\n     * - `spender` cannot be the zero address.\n     */\n    function _approve(address owner, address spender, uint256 amount) internal virtual {\n        require(owner != address(0), \"ERC20: approve from the zero address\");\n        require(spender != address(0), \"ERC20: approve to the zero address\");\n\n        _allowances[owner][spender] = amount;\n        emit Approval(owner, spender, amount);\n    }\n\n    /**\n     * @dev Sets {decimals} to a value other than the default one of 18.\n     *\n     * WARNING: This function should only be called from the constructor. Most\n     * applications that interact with token contracts will not expect\n     * {decimals} to ever change, and may work incorrectly if it does.\n     */\n    function _setupDecimals(uint8 decimals_) internal {\n        _decimals = decimals_;\n    }\n\n    /**\n     * @dev Hook that is called before any transfer of tokens. This includes\n     * minting and burning.\n     *\n     * Calling conditions:\n     *\n     * - when `from` and `to` are both non-zero, `amount` of ``from``\u0027s tokens\n     * will be to transferred to `to`.\n     * - when `from` is zero, `amount` tokens will be minted for `to`.\n     * - when `to` is zero, `amount` of ``from``\u0027s tokens will be burned.\n     * - `from` and `to` are never both zero.\n     *\n     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].\n     */\n    function _beforeTokenTransfer(address from, address to, uint256 amount) internal virtual { }\n}\n"},"IERC20.sol":{"content":"// SPDX-License-Identifier: MIT\n\npragma solidity ^0.6.0;\n\n/**\n * @dev Interface of the ERC20 standard as defined in the EIP.\n */\ninterface IERC20 {\n    /**\n     * @dev Returns the amount of tokens in existence.\n     */\n    function totalSupply() external view returns (uint256);\n\n    /**\n     * @dev Returns the amount of tokens owned by `account`.\n     */\n    function balanceOf(address account) external view returns (uint256);\n\n    /**\n     * @dev Moves `amount` tokens from the caller\u0027s account to `recipient`.\n     *\n     * Returns a boolean value indicating whether the operation succeeded.\n     *\n     * Emits a {Transfer} event.\n     */\n    function transfer(address recipient, uint256 amount) external returns (bool);\n\n    /**\n     * @dev Returns the remaining number of tokens that `spender` will be\n     * allowed to spend on behalf of `owner` through {transferFrom}. This is\n     * zero by default.\n     *\n     * This value changes when {approve} or {transferFrom} are called.\n     */\n    function allowance(address owner, address spender) external view returns (uint256);\n\n    /**\n     * @dev Sets `amount` as the allowance of `spender` over the caller\u0027s tokens.\n     *\n     * Returns a boolean value indicating whether the operation succeeded.\n     *\n     * IMPORTANT: Beware that changing an allowance with this method brings the risk\n     * that someone may use both the old and the new allowance by unfortunate\n     * transaction ordering. One possible solution to mitigate this race\n     * condition is to first reduce the spender\u0027s allowance to 0 and set the\n     * desired value afterwards:\n     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729\n     *\n     * Emits an {Approval} event.\n     */\n    function approve(address spender, uint256 amount) external returns (bool);\n\n    /**\n     * @dev Moves `amount` tokens from `sender` to `recipient` using the\n     * allowance mechanism. `amount` is then deducted from the caller\u0027s\n     * allowance.\n     *\n     * Returns a boolean value indicating whether the operation succeeded.\n     *\n     * Emits a {Transfer} event.\n     */\n    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);\n\n    /**\n     * @dev Emitted when `value` tokens are moved from one account (`from`) to\n     * another (`to`).\n     *\n     * Note that `value` may be zero.\n     */\n    event Transfer(address indexed from, address indexed to, uint256 value);\n\n    /**\n     * @dev Emitted when the allowance of a `spender` for an `owner` is set by\n     * a call to {approve}. `value` is the new allowance.\n     */\n    event Approval(address indexed owner, address indexed spender, uint256 value);\n}\n"},"Ownable.sol":{"content":"// SPDX-License-Identifier: MIT\n\npragma solidity ^0.6.0;\n\nimport \"./Context.sol\";\n/**\n * @dev Contract module which provides a basic access control mechanism, where\n * there is an account (an owner) that can be granted exclusive access to\n * specific functions.\n *\n * By default, the owner account will be the one that deploys the contract. This\n * can later be changed with {transferOwnership}.\n *\n * This module is used through inheritance. It will make available the modifier\n * `onlyOwner`, which can be applied to your functions to restrict their use to\n * the owner.\n */\ncontract Ownable is Context {\n    address private _owner;\n\n    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);\n\n    /**\n     * @dev Initializes the contract setting the deployer as the initial owner.\n     */\n    constructor () internal {\n        address msgSender = _msgSender();\n        _owner = msgSender;\n        emit OwnershipTransferred(address(0), msgSender);\n    }\n\n    /**\n     * @dev Returns the address of the current owner.\n     */\n    function owner() public view returns (address) {\n        return _owner;\n    }\n\n    /**\n     * @dev Throws if called by any account other than the owner.\n     */\n    modifier onlyOwner() {\n        require(_owner == _msgSender(), \"Ownable: caller is not the owner\");\n        _;\n    }\n\n    /**\n     * @dev Leaves the contract without owner. It will not be possible to call\n     * `onlyOwner` functions anymore. Can only be called by the current owner.\n     *\n     * NOTE: Renouncing ownership will leave the contract without an owner,\n     * thereby removing any functionality that is only available to the owner.\n     */\n    function renounceOwnership() public virtual onlyOwner {\n        emit OwnershipTransferred(_owner, address(0));\n        _owner = address(0);\n    }\n\n    /**\n     * @dev Transfers ownership of the contract to a new account (`newOwner`).\n     * Can only be called by the current owner.\n     */\n    function transferOwnership(address newOwner) public virtual onlyOwner {\n        require(newOwner != address(0), \"Ownable: new owner is the zero address\");\n        emit OwnershipTransferred(_owner, newOwner);\n        _owner = newOwner;\n    }\n}\n"},"SafeMath.sol":{"content":"// SPDX-License-Identifier: MIT\n\npragma solidity ^0.6.0;\n\n/**\n * @dev Wrappers over Solidity\u0027s arithmetic operations with added overflow\n * checks.\n *\n * Arithmetic operations in Solidity wrap on overflow. This can easily result\n * in bugs, because programmers usually assume that an overflow raises an\n * error, which is the standard behavior in high level programming languages.\n * `SafeMath` restores this intuition by reverting the transaction when an\n * operation overflows.\n *\n * Using this library instead of the unchecked operations eliminates an entire\n * class of bugs, so it\u0027s recommended to use it always.\n */\nlibrary SafeMath {\n    /**\n     * @dev Returns the addition of two unsigned integers, reverting on\n     * overflow.\n     *\n     * Counterpart to Solidity\u0027s `+` operator.\n     *\n     * Requirements:\n     *\n     * - Addition cannot overflow.\n     */\n    function add(uint256 a, uint256 b) internal pure returns (uint256) {\n        uint256 c = a + b;\n        require(c \u003e= a, \"SafeMath: addition overflow\");\n\n        return c;\n    }\n\n    /**\n     * @dev Returns the subtraction of two unsigned integers, reverting on\n     * overflow (when the result is negative).\n     *\n     * Counterpart to Solidity\u0027s `-` operator.\n     *\n     * Requirements:\n     *\n     * - Subtraction cannot overflow.\n     */\n    function sub(uint256 a, uint256 b) internal pure returns (uint256) {\n        return sub(a, b, \"SafeMath: subtraction overflow\");\n    }\n\n    /**\n     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on\n     * overflow (when the result is negative).\n     *\n     * Counterpart to Solidity\u0027s `-` operator.\n     *\n     * Requirements:\n     *\n     * - Subtraction cannot overflow.\n     */\n    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {\n        require(b \u003c= a, errorMessage);\n        uint256 c = a - b;\n\n        return c;\n    }\n\n    /**\n     * @dev Returns the multiplication of two unsigned integers, reverting on\n     * overflow.\n     *\n     * Counterpart to Solidity\u0027s `*` operator.\n     *\n     * Requirements:\n     *\n     * - Multiplication cannot overflow.\n     */\n    function mul(uint256 a, uint256 b) internal pure returns (uint256) {\n        // Gas optimization: this is cheaper than requiring \u0027a\u0027 not being zero, but the\n        // benefit is lost if \u0027b\u0027 is also tested.\n        // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522\n        if (a == 0) {\n            return 0;\n        }\n\n        uint256 c = a * b;\n        require(c / a == b, \"SafeMath: multiplication overflow\");\n\n        return c;\n    }\n\n    /**\n     * @dev Returns the integer division of two unsigned integers. Reverts on\n     * division by zero. The result is rounded towards zero.\n     *\n     * Counterpart to Solidity\u0027s `/` operator. Note: this function uses a\n     * `revert` opcode (which leaves remaining gas untouched) while Solidity\n     * uses an invalid opcode to revert (consuming all remaining gas).\n     *\n     * Requirements:\n     *\n     * - The divisor cannot be zero.\n     */\n    function div(uint256 a, uint256 b) internal pure returns (uint256) {\n        return div(a, b, \"SafeMath: division by zero\");\n    }\n\n    /**\n     * @dev Returns the integer division of two unsigned integers. Reverts with custom message on\n     * division by zero. The result is rounded towards zero.\n     *\n     * Counterpart to Solidity\u0027s `/` operator. Note: this function uses a\n     * `revert` opcode (which leaves remaining gas untouched) while Solidity\n     * uses an invalid opcode to revert (consuming all remaining gas).\n     *\n     * Requirements:\n     *\n     * - The divisor cannot be zero.\n     */\n    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {\n        require(b \u003e 0, errorMessage);\n        uint256 c = a / b;\n        // assert(a == b * c + a % b); // There is no case in which this doesn\u0027t hold\n\n        return c;\n    }\n\n    /**\n     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),\n     * Reverts when dividing by zero.\n     *\n     * Counterpart to Solidity\u0027s `%` operator. This function uses a `revert`\n     * opcode (which leaves remaining gas untouched) while Solidity uses an\n     * invalid opcode to revert (consuming all remaining gas).\n     *\n     * Requirements:\n     *\n     * - The divisor cannot be zero.\n     */\n    function mod(uint256 a, uint256 b) internal pure returns (uint256) {\n        return mod(a, b, \"SafeMath: modulo by zero\");\n    }\n\n    /**\n     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),\n     * Reverts with custom message when dividing by zero.\n     *\n     * Counterpart to Solidity\u0027s `%` operator. This function uses a `revert`\n     * opcode (which leaves remaining gas untouched) while Solidity uses an\n     * invalid opcode to revert (consuming all remaining gas).\n     *\n     * Requirements:\n     *\n     * - The divisor cannot be zero.\n     */\n    function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {\n        require(b != 0, errorMessage);\n        return a % b;\n    }\n}\n"},"UNCX.sol":{"content":"// SPDX-License-Identifier: MIT\r\n\r\npragma solidity 0.6.12;\r\n\r\nimport \"./Ownable.sol\";\r\nimport \"./ERC20.sol\";\r\n\r\n\r\n// UNCX - UniCrypt with Governance.\r\n// No minting functions exposed in this token contract, max supply is 50k, burn function enabled\r\n\r\ncontract UNCX is ERC20(\"UniCrypt\", \"UNCX\"), Ownable {\r\n\r\n    constructor () public {\r\n      uint256 totalSupply = 50_000e18; // 50k Total supply, no minting functions\r\n      _mint(msg.sender, totalSupply);\r\n      _moveDelegates(address(0), _delegates[msg.sender], totalSupply);\r\n    }\r\n    \r\n    function burn(uint256 amount) public virtual {\r\n        _burn(_msgSender(), amount);\r\n        _moveDelegates(_delegates[msg.sender], address(0), amount);\r\n    }\r\n    \r\n    function _transfer(address sender, address recipient, uint256 amount) internal virtual override {\r\n        super._transfer(sender, recipient, amount);\r\n        _moveDelegates(_delegates[sender], _delegates[recipient], amount);\r\n    }\r\n\r\n    // Copied and modified from YAM code:\r\n    // https://github.com/yam-finance/yam-protocol/blob/master/contracts/token/YAMGovernanceStorage.sol\r\n    // https://github.com/yam-finance/yam-protocol/blob/master/contracts/token/YAMGovernance.sol\r\n    // Which is copied and modified from COMPOUND:\r\n    // https://github.com/compound-finance/compound-protocol/blob/master/contracts/Governance/Comp.sol\r\n\r\n    /// @notice A record of each accounts delegate\r\n    mapping (address =\u003e address) internal _delegates;\r\n\r\n    /// @notice A checkpoint for marking number of votes from a given block\r\n    struct Checkpoint {\r\n        uint32 fromBlock;\r\n        uint256 votes;\r\n    }\r\n\r\n    /// @notice A record of votes checkpoints for each account, by index\r\n    mapping (address =\u003e mapping (uint32 =\u003e Checkpoint)) public checkpoints;\r\n\r\n    /// @notice The number of checkpoints for each account\r\n    mapping (address =\u003e uint32) public numCheckpoints;\r\n\r\n    /// @notice The EIP-712 typehash for the contract\u0027s domain\r\n    bytes32 public constant DOMAIN_TYPEHASH = keccak256(\"EIP712Domain(string name,uint256 chainId,address verifyingContract)\");\r\n\r\n    /// @notice The EIP-712 typehash for the delegation struct used by the contract\r\n    bytes32 public constant DELEGATION_TYPEHASH = keccak256(\"Delegation(address delegatee,uint256 nonce,uint256 expiry)\");\r\n\r\n    /// @notice A record of states for signing / validating signatures\r\n    mapping (address =\u003e uint) public nonces;\r\n\r\n      /// @notice An event thats emitted when an account changes its delegate\r\n    event DelegateChanged(address indexed delegator, address indexed fromDelegate, address indexed toDelegate);\r\n\r\n    /// @notice An event thats emitted when a delegate account\u0027s vote balance changes\r\n    event DelegateVotesChanged(address indexed delegate, uint previousBalance, uint newBalance);\r\n\r\n    /**\r\n     * @notice Delegate votes from `msg.sender` to `delegatee`\r\n     * @param delegator The address to get delegatee for\r\n     */\r\n    function delegates(address delegator)\r\n        external\r\n        view\r\n        returns (address)\r\n    {\r\n        return _delegates[delegator];\r\n    }\r\n\r\n   /**\r\n    * @notice Delegate votes from `msg.sender` to `delegatee`\r\n    * @param delegatee The address to delegate votes to\r\n    */\r\n    function delegate(address delegatee) external {\r\n        return _delegate(msg.sender, delegatee);\r\n    }\r\n\r\n    /**\r\n     * @notice Delegates votes from signatory to `delegatee`\r\n     * @param delegatee The address to delegate votes to\r\n     * @param nonce The contract state required to match the signature\r\n     * @param expiry The time at which to expire the signature\r\n     * @param v The recovery byte of the signature\r\n     * @param r Half of the ECDSA signature pair\r\n     * @param s Half of the ECDSA signature pair\r\n     */\r\n    function delegateBySig(\r\n        address delegatee,\r\n        uint nonce,\r\n        uint expiry,\r\n        uint8 v,\r\n        bytes32 r,\r\n        bytes32 s\r\n    )\r\n        external\r\n    {\r\n        bytes32 domainSeparator = keccak256(\r\n            abi.encode(\r\n                DOMAIN_TYPEHASH,\r\n                keccak256(bytes(name())),\r\n                getChainId(),\r\n                address(this)\r\n            )\r\n        );\r\n\r\n        bytes32 structHash = keccak256(\r\n            abi.encode(\r\n                DELEGATION_TYPEHASH,\r\n                delegatee,\r\n                nonce,\r\n                expiry\r\n            )\r\n        );\r\n\r\n        bytes32 digest = keccak256(\r\n            abi.encodePacked(\r\n                \"\\x19\\x01\",\r\n                domainSeparator,\r\n                structHash\r\n            )\r\n        );\r\n\r\n        address signatory = ecrecover(digest, v, r, s);\r\n        require(signatory != address(0), \"UNCX::delegateBySig: invalid signature\");\r\n        require(nonce == nonces[signatory]++, \"UNCX::delegateBySig: invalid nonce\");\r\n        require(now \u003c= expiry, \"UNCX::delegateBySig: signature expired\");\r\n        return _delegate(signatory, delegatee);\r\n    }\r\n\r\n    /**\r\n     * @notice Gets the current votes balance for `account`\r\n     * @param account The address to get votes balance\r\n     * @return The number of current votes for `account`\r\n     */\r\n    function getCurrentVotes(address account)\r\n        external\r\n        view\r\n        returns (uint256)\r\n    {\r\n        uint32 nCheckpoints = numCheckpoints[account];\r\n        return nCheckpoints \u003e 0 ? checkpoints[account][nCheckpoints - 1].votes : 0;\r\n    }\r\n\r\n    /**\r\n     * @notice Determine the prior number of votes for an account as of a block number\r\n     * @dev Block number must be a finalized block or else this function will revert to prevent misinformation.\r\n     * @param account The address of the account to check\r\n     * @param blockNumber The block number to get the vote balance at\r\n     * @return The number of votes the account had as of the given block\r\n     */\r\n    function getPriorVotes(address account, uint blockNumber)\r\n        external\r\n        view\r\n        returns (uint256)\r\n    {\r\n        require(blockNumber \u003c block.number, \"UNCX::getPriorVotes: not yet determined\");\r\n\r\n        uint32 nCheckpoints = numCheckpoints[account];\r\n        if (nCheckpoints == 0) {\r\n            return 0;\r\n        }\r\n\r\n        // First check most recent balance\r\n        if (checkpoints[account][nCheckpoints - 1].fromBlock \u003c= blockNumber) {\r\n            return checkpoints[account][nCheckpoints - 1].votes;\r\n        }\r\n\r\n        // Next check implicit zero balance\r\n        if (checkpoints[account][0].fromBlock \u003e blockNumber) {\r\n            return 0;\r\n        }\r\n\r\n        uint32 lower = 0;\r\n        uint32 upper = nCheckpoints - 1;\r\n        while (upper \u003e lower) {\r\n            uint32 center = upper - (upper - lower) / 2; // ceil, avoiding overflow\r\n            Checkpoint memory cp = checkpoints[account][center];\r\n            if (cp.fromBlock == blockNumber) {\r\n                return cp.votes;\r\n            } else if (cp.fromBlock \u003c blockNumber) {\r\n                lower = center;\r\n            } else {\r\n                upper = center - 1;\r\n            }\r\n        }\r\n        return checkpoints[account][lower].votes;\r\n    }\r\n\r\n    function _delegate(address delegator, address delegatee)\r\n        internal\r\n    {\r\n        address currentDelegate = _delegates[delegator];\r\n        uint256 delegatorBalance = balanceOf(delegator); // balance of underlying UNCX (not scaled);\r\n        _delegates[delegator] = delegatee;\r\n\r\n        emit DelegateChanged(delegator, currentDelegate, delegatee);\r\n\r\n        _moveDelegates(currentDelegate, delegatee, delegatorBalance);\r\n    }\r\n\r\n    function _moveDelegates(address srcRep, address dstRep, uint256 amount) internal {\r\n        if (srcRep != dstRep \u0026\u0026 amount \u003e 0) {\r\n            if (srcRep != address(0)) {\r\n                // decrease old representative\r\n                uint32 srcRepNum = numCheckpoints[srcRep];\r\n                uint256 srcRepOld = srcRepNum \u003e 0 ? checkpoints[srcRep][srcRepNum - 1].votes : 0;\r\n                uint256 srcRepNew = srcRepOld.sub(amount);\r\n                _writeCheckpoint(srcRep, srcRepNum, srcRepOld, srcRepNew);\r\n            }\r\n\r\n            if (dstRep != address(0)) {\r\n                // increase new representative\r\n                uint32 dstRepNum = numCheckpoints[dstRep];\r\n                uint256 dstRepOld = dstRepNum \u003e 0 ? checkpoints[dstRep][dstRepNum - 1].votes : 0;\r\n                uint256 dstRepNew = dstRepOld.add(amount);\r\n                _writeCheckpoint(dstRep, dstRepNum, dstRepOld, dstRepNew);\r\n            }\r\n        }\r\n    }\r\n\r\n    function _writeCheckpoint(\r\n        address delegatee,\r\n        uint32 nCheckpoints,\r\n        uint256 oldVotes,\r\n        uint256 newVotes\r\n    )\r\n        internal\r\n    {\r\n        uint32 blockNumber = safe32(block.number, \"UNCX::_writeCheckpoint: block number exceeds 32 bits\");\r\n\r\n        if (nCheckpoints \u003e 0 \u0026\u0026 checkpoints[delegatee][nCheckpoints - 1].fromBlock == blockNumber) {\r\n            checkpoints[delegatee][nCheckpoints - 1].votes = newVotes;\r\n        } else {\r\n            checkpoints[delegatee][nCheckpoints] = Checkpoint(blockNumber, newVotes);\r\n            numCheckpoints[delegatee] = nCheckpoints + 1;\r\n        }\r\n\r\n        emit DelegateVotesChanged(delegatee, oldVotes, newVotes);\r\n    }\r\n\r\n    function safe32(uint n, string memory errorMessage) internal pure returns (uint32) {\r\n        require(n \u003c 2**32, errorMessage);\r\n        return uint32(n);\r\n    }\r\n\r\n    function getChainId() internal pure returns (uint) {\r\n        uint256 chainId;\r\n        assembly { chainId := chainid() }\r\n        return chainId;\r\n    }\r\n}"}}