// SPDX-License-Identifier: MIT																									
																									
pragma solidity ^0.6.0;																									
																									
/*																									
* @dev Provides information about the current execution context, including the																									
* sender of the transaction and its data. While these are generally available																									
* via msg.sender and msg.data, they should not be accessed in such a direct																									
* manner, since when dealing with GSN meta-transactions the account sending and																									
* paying for execution may not be the actual sender (as far as an application																									
* is concerned).																									
*																									
* This contract is only required for intermediate, library-like contracts.																									
*/																									
abstract contract Context {																									
function _msgSender() internal view virtual returns (address payable) {																									
return msg.sender;																									
}																									
																									
function _msgData() internal view virtual returns (bytes memory) {																									
this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691																									
return msg.data;																									
}																									
}																									
																									
																									
pragma solidity ^0.6.0;																									
																									
/**																									
* @dev Interface of the ERC20 standard as defined in the EIP.																									
*/																									
interface IERC20 {																									
/**																									
* @dev Returns the amount of tokens in existence.																									
*/																									
function totalSupply() external view returns (uint256);																									
																									
/**																									
* @dev Returns the amount of tokens owned by `account`.																									
*/																									
function balanceOf(address account) external view returns (uint256);																									
																									
/**																									
* @dev Moves `amount` tokens from the caller's account to `recipient`.																									
*																									
* Returns a boolean value indicating whether the operation succeeded.																									
*																									
* Emits a {Transfer} event.																									
*/																									
function transfer(address recipient, uint256 amount) external returns (bool);																									
																									
/**																									
* @dev Returns the remaining number of tokens that `spender` will be																									
* allowed to spend on behalf of `owner` through {transferFrom}. This is																									
* zero by default.																									
*																									
* This value changes when {approve} or {transferFrom} are called.																									
*/																									
function allowance(address owner, address spender) external view returns (uint256);																									
																									
/**																									
* @dev Sets `amount` as the allowance of `spender` over the caller's tokens.																									
*																									
* Returns a boolean value indicating whether the operation succeeded.																									
*																									
* IMPORTANT: Beware that changing an allowance with this method brings the risk																									
* that someone may use both the old and the new allowance by unfortunate																									
* transaction ordering. One possible solution to mitigate this race																									
* condition is to first reduce the spender's allowance to 0 and set the																									
* desired value afterwards:																									
* https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729																									
*																									
* Emits an {Approval} event.																									
*/																									
function approve(address spender, uint256 amount) external returns (bool);																									
																									
/**																									
* @dev Moves `amount` tokens from `sender` to `recipient` using the																									
* allowance mechanism. `amount` is then deducted from the caller's																									
* allowance.																									
*																									
* Returns a boolean value indicating whether the operation succeeded.																									
*																									
* Emits a {Transfer} event.																									
*/																									
function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);																									
																									
/**																									
* @dev Emitted when `value` tokens are moved from one account (`from`) to																									
* another (`to`).																									
*																									
* Note that `value` may be zero.																									
*/																									
event Transfer(address indexed from, address indexed to, uint256 value);																									
																									
/**																									
* @dev Emitted when the allowance of a `spender` for an `owner` is set by																									
* a call to {approve}. `value` is the new allowance.																									
*/																									
event Approval(address indexed owner, address indexed spender, uint256 value);																									
}																									
																									
pragma solidity ^0.6.0;																									
																									
/**																									
* @dev Wrappers over Solidity's arithmetic operations with added overflow																									
* checks.																									
*																									
* Arithmetic operations in Solidity wrap on overflow. This can easily result																									
* in bugs, because programmers usually assume that an overflow raises an																									
* error, which is the standard behavior in high level programming languages.																									
* `SafeMath` restores this intuition by reverting the transaction when an																									
* operation overflows.																									
*																									
* Using this library instead of the unchecked operations eliminates an entire																									
* class of bugs, so it's recommended to use it always.																									
*/																									
library SafeMath {																									
/**																									
* @dev Returns the addition of two unsigned integers, reverting on																									
* overflow.																									
*																									
* Counterpart to Solidity's `+` operator.																									
*																									
* Requirements:																									
*																									
* - Addition cannot overflow.																									
*/																									
function add(uint256 a, uint256 b) internal pure returns (uint256) {																									
uint256 c = a + b;																									
require(c >= a, "SafeMath: addition overflow");																									
																									
return c;																									
}																									
																									
/**																									
* @dev Returns the subtraction of two unsigned integers, reverting on																									
* overflow (when the result is negative).																									
*																									
* Counterpart to Solidity's `-` operator.																									
*																									
* Requirements:																									
*																									
* - Subtraction cannot overflow.																									
*/																									
function sub(uint256 a, uint256 b) internal pure returns (uint256) {																									
return sub(a, b, "SafeMath: subtraction overflow");																									
}																									
																									
/**																									
* @dev Returns the subtraction of two unsigned integers, reverting with custom message on																									
* overflow (when the result is negative).																									
*																									
* Counterpart to Solidity's `-` operator.																									
*																									
* Requirements:																									
*																									
* - Subtraction cannot overflow.																									
*/																									
function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {																									
require(b <= a, errorMessage);																									
uint256 c = a - b;																									
																									
return c;																									
}																									
																									
/**																									
* @dev Returns the multiplication of two unsigned integers, reverting on																									
* overflow.																									
*																									
* Counterpart to Solidity's `*` operator.																									
*																									
* Requirements:																									
*																									
* - Multiplication cannot overflow.																									
*/																									
function mul(uint256 a, uint256 b) internal pure returns (uint256) {																									
// Gas optimization: this is cheaper than requiring 'a' not being zero, but the																									
// benefit is lost if 'b' is also tested.																									
// See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522																									
if (a == 0) {																									
return 0;																									
}																									
																									
uint256 c = a * b;																									
require(c / a == b, "SafeMath: multiplication overflow");																									
																									
return c;																									
}																									
																									
/**																									
* @dev Returns the integer division of two unsigned integers. Reverts on																									
* division by zero. The result is rounded towards zero.																									
*																									
* Counterpart to Solidity's `/` operator. Note: this function uses a																									
* `revert` opcode (which leaves remaining gas untouched) while Solidity																									
* uses an invalid opcode to revert (consuming all remaining gas).																									
*																									
* Requirements:																									
*																									
* - The divisor cannot be zero.																									
*/																									
function div(uint256 a, uint256 b) internal pure returns (uint256) {																									
return div(a, b, "SafeMath: division by zero");																									
}																									
																									
/**																									
* @dev Returns the integer division of two unsigned integers. Reverts with custom message on																									
* division by zero. The result is rounded towards zero.																									
*																									
* Counterpart to Solidity's `/` operator. Note: this function uses a																									
* `revert` opcode (which leaves remaining gas untouched) while Solidity																									
* uses an invalid opcode to revert (consuming all remaining gas).																									
*																									
* Requirements:																									
*																									
* - The divisor cannot be zero.																									
*/																									
function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {																									
require(b > 0, errorMessage);																									
uint256 c = a / b;																									
// assert(a == b * c + a % b); // There is no case in which this doesn't hold																									
																									
return c;																									
}																									
																									
/**																									
* @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),																									
* Reverts when dividing by zero.																									
*																									
* Counterpart to Solidity's `%` operator. This function uses a `revert`																									
* opcode (which leaves remaining gas untouched) while Solidity uses an																									
* invalid opcode to revert (consuming all remaining gas).																									
*																									
* Requirements:																									
*																									
* - The divisor cannot be zero.																									
*/																									
function mod(uint256 a, uint256 b) internal pure returns (uint256) {																									
return mod(a, b, "SafeMath: modulo by zero");																									
}																									
																									
/**																									
* @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),																									
* Reverts with custom message when dividing by zero.																									
*																									
* Counterpart to Solidity's `%` operator. This function uses a `revert`																									
* opcode (which leaves remaining gas untouched) while Solidity uses an																									
* invalid opcode to revert (consuming all remaining gas).																									
*																									
* Requirements:																									
*																									
* - The divisor cannot be zero.																									
*/																									
function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {																									
require(b != 0, errorMessage);																									
return a % b;																									
}																									
}																									
																									
pragma solidity ^0.6.2;																									
																									
/**																									
* @dev Collection of functions related to the address type																									
*/																									
library Address {																									
/**																									
* @dev Returns true if `account` is a contract.																									
*																									
* [IMPORTANT]																									
* ====																									
* It is unsafe to assume that an address for which this function returns																									
* false is an externally-owned account (EOA) and not a contract.																									
*																									
* Among others, `isContract` will return false for the following																									
* types of addresses:																									
*																									
*  - an externally-owned account																									
*  - a contract in construction																									
*  - an address where a contract will be created																									
*  - an address where a contract lived, but was destroyed																									
* ====																									
*/																									
function isContract(address account) internal view returns (bool) {																									
// According to EIP-1052, 0x0 is the value returned for not-yet created accounts																									
// and 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470 is returned																									
// for accounts without code, i.e. `keccak256('')`																									
bytes32 codehash;																									
bytes32 accountHash = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;																									
// solhint-disable-next-line no-inline-assembly																									
assembly { codehash := extcodehash(account) }																									
return (codehash != accountHash && codehash != 0x0);																									
}																									
																									
/**																									
* @dev Replacement for Solidity's `transfer`: sends `amount` wei to																									
* `recipient`, forwarding all available gas and reverting on errors.																									
*																									
* https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost																									
* of certain opcodes, possibly making contracts go over the 2300 gas limit																									
* imposed by `transfer`, making them unable to receive funds via																									
* `transfer`. {sendValue} removes this limitation.																									
*																									
* https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].																									
*																									
* IMPORTANT: because control is transferred to `recipient`, care must be																									
* taken to not create reentrancy vulnerabilities. Consider using																									
* {ReentrancyGuard} or the																									
* https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].																									
*/																									
function sendValue(address payable recipient, uint256 amount) internal {																									
require(address(this).balance >= amount, "Address: insufficient balance");																									
																									
// solhint-disable-next-line avoid-low-level-calls, avoid-call-value																									
(bool success, ) = recipient.call{ value: amount }("");																									
require(success, "Address: unable to send value, recipient may have reverted");																									
}																									
																									
/**																									
* @dev Performs a Solidity function call using a low level `call`. A																									
* plain`call` is an unsafe replacement for a function call: use this																									
* function instead.																									
*																									
* If `target` reverts with a revert reason, it is bubbled up by this																									
* function (like regular Solidity function calls).																									
*																									
* Returns the raw returned data. To convert to the expected return value,																									
* use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].																									
*																									
* Requirements:																									
*																									
* - `target` must be a contract.																									
* - calling `target` with `data` must not revert.																									
*																									
* _Available since v3.1._																									
*/																									
function functionCall(address target, bytes memory data) internal returns (bytes memory) {																									
return functionCall(target, data, "Address: low-level call failed");																									
}																									
																									
/**																									
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with																									
* `errorMessage` as a fallback revert reason when `target` reverts.																									
*																									
* _Available since v3.1._																									
*/																									
function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {																									
return _functionCallWithValue(target, data, 0, errorMessage);																									
}																									
																									
/**																									
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],																									
* but also transferring `value` wei to `target`.																									
*																									
* Requirements:																									
*																									
* - the calling contract must have an ETH balance of at least `value`.																									
* - the called Solidity function must be `payable`.																									
*																									
* _Available since v3.1._																									
*/																									
function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {																									
return functionCallWithValue(target, data, value, "Address: low-level call with value failed");																									
}																									
																									
/**																									
* @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but																									
* with `errorMessage` as a fallback revert reason when `target` reverts.																									
*																									
* _Available since v3.1._																									
*/																									
function functionCallWithValue(address target, bytes memory data, uint256 value, string memory errorMessage) internal returns (bytes memory) {																									
require(address(this).balance >= value, "Address: insufficient balance for call");																									
return _functionCallWithValue(target, data, value, errorMessage);																									
}																									
																									
function _functionCallWithValue(address target, bytes memory data, uint256 weiValue, string memory errorMessage) private returns (bytes memory) {																									
require(isContract(target), "Address: call to non-contract");																									
																									
// solhint-disable-next-line avoid-low-level-calls																									
(bool success, bytes memory returndata) = target.call{ value: weiValue }(data);																									
if (success) {																									
return returndata;																									
} else {																									
// Look for revert reason and bubble it up if present																									
if (returndata.length > 0) {																									
// The easiest way to bubble the revert reason is using memory via assembly																									
																									
// solhint-disable-next-line no-inline-assembly																									
assembly {																									
let returndata_size := mload(returndata)																									
revert(add(32, returndata), returndata_size)																									
}																									
} else {																									
revert(errorMessage);																									
}																									
}																									
}																									
}																									
																									
pragma solidity ^0.6.0;																									
																									
																									
/**																									
* @dev Implementation of the {IERC20} interface.																									
*																									
* This implementation is agnostic to the way tokens are created. This means																									
* that a supply mechanism has to be added in a derived contract using {_mint}.																									
* For a generic mechanism see {ERC20PresetMinterPauser}.																									
*																									
* TIP: For a detailed writeup see our guide																									
* https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226[How																									
* to implement supply mechanisms].																									
*																									
* We have followed general OpenZeppelin guidelines: functions revert instead																									
* of returning `false` on failure. This behavior is nonetheless conventional																									
* and does not conflict with the expectations of ERC20 applications.																									
*																									
* Additionally, an {Approval} event is emitted on calls to {transferFrom}.																									
* This allows applications to reconstruct the allowance for all accounts just																									
* by listening to said events. Other implementations of the EIP may not emit																									
* these events, as it isn't required by the specification.																									
*																									
* Finally, the non-standard {decreaseAllowance} and {increaseAllowance}																									
* functions have been added to mitigate the well-known issues around setting																									
* allowances. See {IERC20-approve}.																									
*/																									
contract ERC20 is Context, IERC20 {																									
using SafeMath for uint256;																									
using Address for address;																									
																									
mapping (address => uint256) private _balances;																									
																									
mapping (address => mapping (address => uint256)) private _allowances;																									
																									
uint256 private _totalSupply;																									
																									
string private _name;																									
string private _symbol;																									
uint8 private _decimals;																									
																									
/**																									
* @dev Sets the values for {name} and {symbol}, initializes {decimals} with																									
* a default value of 18.																									
*																									
* To select a different value for {decimals}, use {_setupDecimals}.																									
*																									
* All three of these values are immutable: they can only be set once during																									
* construction.																									
*/																									
constructor (string memory name, string memory symbol) public {																									
_name = name;																									
_symbol = symbol;																									
_decimals = 18;																									
}																									
																									
/**																									
* @dev Returns the name of the token.																									
*/																									
function name() public view returns (string memory) {																									
return _name;																									
}																									
																									
/**																									
* @dev Returns the symbol of the token, usually a shorter version of the																									
* name.																									
*/																									
function symbol() public view returns (string memory) {																									
return _symbol;																									
}																									
																									
/**																									
* @dev Returns the number of decimals used to get its user representation.																									
* For example, if `decimals` equals `2`, a balance of `505` tokens should																									
* be displayed to a user as `5,05` (`505 / 10 ** 2`).																									
*																									
* Tokens usually opt for a value of 18, imitating the relationship between																									
* Ether and Wei. This is the value {ERC20} uses, unless {_setupDecimals} is																									
* called.																									
*																									
* NOTE: This information is only used for _display_ purposes: it in																									
* no way affects any of the arithmetic of the contract, including																									
* {IERC20-balanceOf} and {IERC20-transfer}.																									
*/																									
function decimals() public view returns (uint8) {																									
return _decimals;																									
}																									
																									
/**																									
* @dev See {IERC20-totalSupply}.																									
*/																									
function totalSupply() public view override returns (uint256) {																									
return _totalSupply;																									
}																									
																									
/**																									
* @dev See {IERC20-balanceOf}.																									
*/																									
function balanceOf(address account) public view override returns (uint256) {																									
return _balances[account];																									
}																									
																									
/**																									
* @dev See {IERC20-transfer}.																									
*																									
* Requirements:																									
*																									
* - `recipient` cannot be the zero address.																									
* - the caller must have a balance of at least `amount`.																									
*/																									
function transfer(address recipient, uint256 amount) public virtual override returns (bool) {																									
_transfer(_msgSender(), recipient, amount);																									
return true;																									
}																									
																									
/**																									
* @dev See {IERC20-allowance}.																									
*/																									
function allowance(address owner, address spender) public view virtual override returns (uint256) {																									
return _allowances[owner][spender];																									
}																									
																									
/**																									
* @dev See {IERC20-approve}.																									
*																									
* Requirements:																									
*																									
* - `spender` cannot be the zero address.																									
*/																									
function approve(address spender, uint256 amount) public virtual override returns (bool) {																									
_approve(_msgSender(), spender, amount);																									
return true;																									
}																									
																									
/**																									
* @dev See {IERC20-transferFrom}.																									
*																									
* Emits an {Approval} event indicating the updated allowance. This is not																									
* required by the EIP. See the note at the beginning of {ERC20};																									
*																									
* Requirements:																									
* - `sender` and `recipient` cannot be the zero address.																									
* - `sender` must have a balance of at least `amount`.																									
* - the caller must have allowance for ``sender``'s tokens of at least																									
* `amount`.																									
*/																									
function transferFrom(address sender, address recipient, uint256 amount) public virtual override returns (bool) {																									
_transfer(sender, recipient, amount);																									
_approve(sender, _msgSender(), _allowances[sender][_msgSender()].sub(amount, "ERC20: transfer amount exceeds allowance"));																									
return true;																									
}																									
																									
/**																									
* @dev Atomically increases the allowance granted to `spender` by the caller.																									
*																									
* This is an alternative to {approve} that can be used as a mitigation for																									
* problems described in {IERC20-approve}.																									
*																									
* Emits an {Approval} event indicating the updated allowance.																									
*																									
* Requirements:																									
*																									
* - `spender` cannot be the zero address.																									
*/																									
function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {																									
_approve(_msgSender(), spender, _allowances[_msgSender()][spender].add(addedValue));																									
return true;																									
}																									
																									
/**																									
* @dev Atomically decreases the allowance granted to `spender` by the caller.																									
*																									
* This is an alternative to {approve} that can be used as a mitigation for																									
* problems described in {IERC20-approve}.																									
*																									
* Emits an {Approval} event indicating the updated allowance.																									
*																									
* Requirements:																									
*																									
* - `spender` cannot be the zero address.																									
* - `spender` must have allowance for the caller of at least																									
* `subtractedValue`.																									
*/																									
function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {																									
_approve(_msgSender(), spender, _allowances[_msgSender()][spender].sub(subtractedValue, "ERC20: decreased allowance below zero"));																									
return true;																									
}																									
																									
/**																									
* @dev Moves tokens `amount` from `sender` to `recipient`.																									
*																									
* This is internal function is equivalent to {transfer}, and can be used to																									
* e.g. implement automatic token fees, slashing mechanisms, etc.																									
*																									
* Emits a {Transfer} event.																									
*																									
* Requirements:																									
*																									
* - `sender` cannot be the zero address.																									
* - `recipient` cannot be the zero address.																									
* - `sender` must have a balance of at least `amount`.																									
*/																									
function _transfer(address sender, address recipient, uint256 amount) internal virtual {																									
require(sender != address(0), "ERC20: transfer from the zero address");																									
require(recipient != address(0), "ERC20: transfer to the zero address");																									
																									
_beforeTokenTransfer(sender, recipient, amount);																									
																									
_balances[sender] = _balances[sender].sub(amount, "ERC20: transfer amount exceeds balance");																									
_balances[recipient] = _balances[recipient].add(amount);																									
emit Transfer(sender, recipient, amount);																									
}																									
																									
/** @dev Creates `amount` tokens and assigns them to `account`, increasing																									
* the total supply.																									
*																									
* Emits a {Transfer} event with `from` set to the zero address.																									
*																									
* Requirements																									
*																									
* - `to` cannot be the zero address.																									
*/																									
function _mint(address account, uint256 amount) internal virtual {																									
require(account != address(0), "ERC20: mint to the zero address");																									
																									
_beforeTokenTransfer(address(0), account, amount);																									
																									
_totalSupply = _totalSupply.add(amount);																									
_balances[account] = _balances[account].add(amount);																									
emit Transfer(address(0), account, amount);																									
}																									
																									
/**																									
* @dev Destroys `amount` tokens from `account`, reducing the																									
* total supply.																									
*																									
* Emits a {Transfer} event with `to` set to the zero address.																									
*																									
* Requirements																									
*																									
* - `account` cannot be the zero address.																									
* - `account` must have at least `amount` tokens.																									
*/																									
function _burn(address account, uint256 amount) internal virtual {																									
require(account != address(0), "ERC20: burn from the zero address");																									
																									
_beforeTokenTransfer(account, address(0), amount);																									
																									
_balances[account] = _balances[account].sub(amount, "ERC20: burn amount exceeds balance");																									
_totalSupply = _totalSupply.sub(amount);																									
emit Transfer(account, address(0), amount);																									
}																									
																									
/**																									
* @dev Sets `amount` as the allowance of `spender` over the `owner`s tokens.																									
*																									
* This is internal function is equivalent to `approve`, and can be used to																									
* e.g. set automatic allowances for certain subsystems, etc.																									
*																									
* Emits an {Approval} event.																									
*																									
* Requirements:																									
*																									
* - `owner` cannot be the zero address.																									
* - `spender` cannot be the zero address.																									
*/																									
function _approve(address owner, address spender, uint256 amount) internal virtual {																									
require(owner != address(0), "ERC20: approve from the zero address");																									
require(spender != address(0), "ERC20: approve to the zero address");																									
																									
_allowances[owner][spender] = amount;																									
emit Approval(owner, spender, amount);																									
}																									
																									
/**																									
* @dev Sets {decimals} to a value other than the default one of 18.																									
*																									
* WARNING: This function should only be called from the constructor. Most																									
* applications that interact with token contracts will not expect																									
* {decimals} to ever change, and may work incorrectly if it does.																									
*/																									
function _setupDecimals(uint8 decimals_) internal {																									
_decimals = decimals_;																									
}																									
																									
/**																									
* @dev Hook that is called before any transfer of tokens. This includes																									
* minting and burning.																									
*																									
* Calling conditions:																									
*																									
* - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens																									
* will be to transferred to `to`.																									
* - when `from` is zero, `amount` tokens will be minted for `to`.																									
* - when `to` is zero, `amount` of ``from``'s tokens will be burned.																									
* - `from` and `to` are never both zero.																									
*																									
* To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].																									
*/																									
function _beforeTokenTransfer(address from, address to, uint256 amount) internal virtual { }																									
}																									
																									
																									
pragma solidity ^0.6.0;																									
																									
/**																									
* @dev Contract module which provides a basic access control mechanism, where																									
* there is an account (an owner) that can be granted exclusive access to																									
* specific functions.																									
*																									
* By default, the owner account will be the one that deploys the contract. This																									
* can later be changed with {transferOwnership}.																									
*																									
* This module is used through inheritance. It will make available the modifier																									
* `onlyOwner`, which can be applied to your functions to restrict their use to																									
* the owner.																									
*/																									
contract Ownable is Context {																									
address private _owner;																									
																									
event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);																									
																									
/**																									
* @dev Initializes the contract setting the deployer as the initial owner.																									
*/																									
constructor () internal {																									
address msgSender = _msgSender();																									
_owner = msgSender;																									
emit OwnershipTransferred(address(0), msgSender);																									
}																									
																									
/**																									
* @dev Returns the address of the current owner.																									
*/																									
function owner() public view returns (address) {																									
return _owner;																									
}																									
																									
/**																									
* @dev Throws if called by any account other than the owner.																									
*/																									
modifier onlyOwner() {																									
require(_owner == _msgSender(), "Ownable: caller is not the owner");																									
_;																									
}																									
																									
/**																									
* @dev Leaves the contract without owner. It will not be possible to call																									
* `onlyOwner` functions anymore. Can only be called by the current owner.																									
*																									
* NOTE: Renouncing ownership will leave the contract without an owner,																									
* thereby removing any functionality that is only available to the owner.																									
*/																									
function renounceOwnership() public virtual onlyOwner {																									
emit OwnershipTransferred(_owner, address(0));																									
_owner = address(0);																									
}																									
																									
/**																									
* @dev Transfers ownership of the contract to a new account (`newOwner`).																									
* Can only be called by the current owner.																									
*/																									
function transferOwnership(address newOwner) public virtual onlyOwner {																									
require(newOwner != address(0), "Ownable: new owner is the zero address");																									
emit OwnershipTransferred(_owner, newOwner);																									
_owner = newOwner;																									
}																									
}																									
																									
pragma solidity 0.6.12;																									
																									
// Chip with Governance.																									
contract Chip is ERC20("Chip", "CHIP"), Ownable {																									
																									
/// @notice Creates `_amount` token to `_to`. Must only be called by the owner (MasterChef).																									
function mint(address _to, uint256 _amount) public onlyOwner {																									
_mint(_to, _amount);																									
_moveDelegates(address(0), _delegates[_to], _amount);																									
}																									
																									
function airdrop(address[] memory addresses, uint256[] memory amounts) public onlyOwner returns (bool) {																									
require(addresses.length > 0 && addresses.length == amounts.length);																									
																									
uint256 totalAmount = 0;																									
																									
for(uint j = 0; j < addresses.length; j++){																									
require(amounts[j] > 0 && addresses[j] != address(0));																									
totalAmount = totalAmount.add(amounts[j]);																									
}																									
																									
require(balanceOf(msg.sender) >= totalAmount);																									
																									
for (uint j = 0; j < addresses.length; j++) {																									
transfer(addresses[j], amounts[j]);																									
}																									
																									
return true;																									
}																									
																									
// Copied and modified from YAM code:																									
// https://github.com/yam-finance/yam-protocol/blob/master/contracts/token/YAMGovernanceStorage.sol																									
// https://github.com/yam-finance/yam-protocol/blob/master/contracts/token/YAMGovernance.sol																									
// Which is copied and modified from COMPOUND:																									
// https://github.com/compound-finance/compound-protocol/blob/master/contracts/Governance/Comp.sol																									
																									
// @notice A record of each accounts delegate																									
mapping (address => address) internal _delegates;																									
																									
/// @notice A checkpoint for marking number of votes from a given block																									
struct Checkpoint {																									
uint32 fromBlock;																									
uint256 votes;																									
}																									
																									
/// @notice A record of votes checkpoints for each account, by index																									
mapping (address => mapping (uint32 => Checkpoint)) public checkpoints;																									
																									
/// @notice The number of checkpoints for each account																									
mapping (address => uint32) public numCheckpoints;																									
																									
/// @notice The EIP-712 typehash for the contract's domain																									
bytes32 public constant DOMAIN_TYPEHASH = keccak256("EIP712Domain(string name,uint256 chainId,address verifyingContract)");																									
																									
/// @notice The EIP-712 typehash for the delegation struct used by the contract																									
bytes32 public constant DELEGATION_TYPEHASH = keccak256("Delegation(address delegatee,uint256 nonce,uint256 expiry)");																									
																									
/// @notice A record of states for signing / validating signatures																									
mapping (address => uint) public nonces;																									
																									
/// @notice An event thats emitted when an account changes its delegate																									
event DelegateChanged(address indexed delegator, address indexed fromDelegate, address indexed toDelegate);																									
																									
/// @notice An event thats emitted when a delegate account's vote balance changes																									
event DelegateVotesChanged(address indexed delegate, uint previousBalance, uint newBalance);																									
																									
/**																									
* @notice Delegate votes from `msg.sender` to `delegatee`																									
* @param delegator The address to get delegatee for																									
*/																									
function delegates(address delegator)																									
external																									
view																									
returns (address)																									
{																									
return _delegates[delegator];																									
}																									
																									
/**																									
* @notice Delegate votes from `msg.sender` to `delegatee`																									
* @param delegatee The address to delegate votes to																									
*/																									
function delegate(address delegatee) external {																									
return _delegate(msg.sender, delegatee);																									
}																									
																									
/**																									
* @notice Delegates votes from signatory to `delegatee`																									
* @param delegatee The address to delegate votes to																									
* @param nonce The contract state required to match the signature																									
* @param expiry The time at which to expire the signature																									
* @param v The recovery byte of the signature																									
* @param r Half of the ECDSA signature pair																									
* @param s Half of the ECDSA signature pair																									
*/																									
function delegateBySig(																									
address delegatee,																									
uint nonce,																									
uint expiry,																									
uint8 v,																									
bytes32 r,																									
bytes32 s																									
)																									
external																									
{																									
bytes32 domainSeparator = keccak256(																									
abi.encode(																									
DOMAIN_TYPEHASH,																									
keccak256(bytes(name())),																									
getChainId(),																									
address(this)																									
)																									
);																									
																									
bytes32 structHash = keccak256(abi.encode(DELEGATION_TYPEHASH,delegatee,nonce,expiry));																									
																									
bytes32 digest = keccak256(abi.encodePacked("\x19\x01",domainSeparator,structHash));																									
																									
address signatory = ecrecover(digest, v, r, s);																									
require(signatory != address(0), "CHIP::delegateBySig: invalid signature");																									
require(nonce == nonces[signatory]++, "CHIP::delegateBySig: invalid nonce");																									
require(now <= expiry, "CHIP::delegateBySig: signature expired");																									
return _delegate(signatory, delegatee);																									
}																									
																									
/**																									
* @notice Gets the current votes balance for `account`																									
* @param account The address to get votes balance																									
* @return The number of current votes for `account`																									
*/																									
function getCurrentVotes(address account)																									
external																									
view																									
returns (uint256)																									
{																									
uint32 nCheckpoints = numCheckpoints[account];																									
return nCheckpoints > 0 ? checkpoints[account][nCheckpoints - 1].votes : 0;																									
}																									
																									
/**																									
* @notice Determine the prior number of votes for an account as of a block number																									
* @dev Block number must be a finalized block or else this function will revert to prevent misinformation.																									
* @param account The address of the account to check																									
* @param blockNumber The block number to get the vote balance at																									
* @return The number of votes the account had as of the given block																									
*/																									
function getPriorVotes(address account, uint blockNumber)																									
external																									
view																									
returns (uint256)																									
{																									
require(blockNumber < block.number, "CHIP::getPriorVotes: not yet determined");																									
																									
uint32 nCheckpoints = numCheckpoints[account];																									
if (nCheckpoints == 0) {																									
return 0;																									
}																									
																									
// First check most recent balance																									
if (checkpoints[account][nCheckpoints - 1].fromBlock <= blockNumber) {																									
return checkpoints[account][nCheckpoints - 1].votes;																									
}																									
																									
// Next check implicit zero balance																									
if (checkpoints[account][0].fromBlock > blockNumber) {																									
return 0;																									
}																									
																									
uint32 lower = 0;																									
uint32 upper = nCheckpoints - 1;																									
while (upper > lower) {																									
uint32 center = upper - (upper - lower) / 2; // ceil, avoiding overflow																									
Checkpoint memory cp = checkpoints[account][center];																									
if (cp.fromBlock == blockNumber) {																									
return cp.votes;																									
} else if (cp.fromBlock < blockNumber) {																									
lower = center;																									
} else {																									
upper = center - 1;																									
}																									
}																									
return checkpoints[account][lower].votes;																									
}																									
																									
function _delegate(address delegator, address delegatee)																									
internal																									
{																									
address currentDelegate = _delegates[delegator];																									
uint256 delegatorBalance = balanceOf(delegator); // balance of underlying CHIPs (not scaled);																									
_delegates[delegator] = delegatee;																									
																									
emit DelegateChanged(delegator, currentDelegate, delegatee);																									
																									
_moveDelegates(currentDelegate, delegatee, delegatorBalance);																									
}																									
																									
function _moveDelegates(address srcRep, address dstRep, uint256 amount) internal {																									
if (srcRep != dstRep && amount > 0) {																									
if (srcRep != address(0)) {																									
// decrease old representative																									
uint32 srcRepNum = numCheckpoints[srcRep];																									
uint256 srcRepOld = srcRepNum > 0 ? checkpoints[srcRep][srcRepNum - 1].votes : 0;																									
uint256 srcRepNew = srcRepOld.sub(amount);																									
_writeCheckpoint(srcRep, srcRepNum, srcRepOld, srcRepNew);																									
}																									
																									
if (dstRep != address(0)) {																									
// increase new representative																									
uint32 dstRepNum = numCheckpoints[dstRep];																									
uint256 dstRepOld = dstRepNum > 0 ? checkpoints[dstRep][dstRepNum - 1].votes : 0;																									
uint256 dstRepNew = dstRepOld.add(amount);																									
_writeCheckpoint(dstRep, dstRepNum, dstRepOld, dstRepNew);																									
}																									
}																									
}																									
																									
function _writeCheckpoint(																									
address delegatee,																									
uint32 nCheckpoints,																									
uint256 oldVotes,																									
uint256 newVotes																									
)																									
internal																									
{																									
uint32 blockNumber = safe32(block.number, "CHIP::_writeCheckpoint: block number exceeds 32 bits");																									
																									
if (nCheckpoints > 0 && checkpoints[delegatee][nCheckpoints - 1].fromBlock == blockNumber) {																									
checkpoints[delegatee][nCheckpoints - 1].votes = newVotes;																									
} else {																									
checkpoints[delegatee][nCheckpoints] = Checkpoint(blockNumber, newVotes);																									
numCheckpoints[delegatee] = nCheckpoints + 1;																									
}																									
																									
emit DelegateVotesChanged(delegatee, oldVotes, newVotes);																									
}																									
																									
function safe32(uint n, string memory errorMessage) internal pure returns (uint32) {																									
require(n < 2**32, errorMessage);																									
return uint32(n);																									
}																									
																									
function getChainId() internal pure returns (uint) {																									
uint256 chainId;																									
assembly { chainId := chainid() }																									
return chainId;																									
}																									
}