// SPDX-License-Identifier: MIT

pragma solidity =0.6.12;


// 
/**
 * @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);
}

// 
/**
 * @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;
    }
}

// 
/**
 * @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) {
        // This method relies in extcodesize, which returns 0 for contracts in
        // construction, since the code is only stored at the end of the
        // constructor execution.

        uint256 size;
        // solhint-disable-next-line no-inline-assembly
        assembly { size := extcodesize(account) }
        return size > 0;
    }

    /**
     * @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);
            }
        }
    }
}

// 
/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeERC20 {
    using SafeMath for uint256;
    using Address for address;

    function safeTransfer(IERC20 token, address to, uint256 value) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }

    function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
    }

    /**
     * @dev Deprecated. This function has issues similar to the ones found in
     * {IERC20-approve}, and its usage is discouraged.
     *
     * Whenever possible, use {safeIncreaseAllowance} and
     * {safeDecreaseAllowance} instead.
     */
    function safeApprove(IERC20 token, address spender, uint256 value) internal {
        // safeApprove should only be called when setting an initial allowance,
        // or when resetting it to zero. To increase and decrease it, use
        // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
        // solhint-disable-next-line max-line-length
        require((value == 0) || (token.allowance(address(this), spender) == 0),
            "SafeERC20: approve from non-zero to non-zero allowance"
        );
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
    }

    function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 newAllowance = token.allowance(address(this), spender).add(value);
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 newAllowance = token.allowance(address(this), spender).sub(value, "SafeERC20: decreased allowance below zero");
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     */
    function _callOptionalReturn(IERC20 token, bytes memory data) private {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves. We use {Address.functionCall} to perform this call, which verifies that
        // the target address contains contract code and also asserts for success in the low-level call.

        bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
        if (returndata.length > 0) { // Return data is optional
            // solhint-disable-next-line max-line-length
            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
        }
    }
}

// 
/**
 * @dev Library for managing
 * https://en.wikipedia.org/wiki/Set_(abstract_data_type)[sets] of primitive
 * types.
 *
 * Sets have the following properties:
 *
 * - Elements are added, removed, and checked for existence in constant time
 * (O(1)).
 * - Elements are enumerated in O(n). No guarantees are made on the ordering.
 *
 * ```
 * contract Example {
 *     // Add the library methods
 *     using EnumerableSet for EnumerableSet.AddressSet;
 *
 *     // Declare a set state variable
 *     EnumerableSet.AddressSet private mySet;
 * }
 * ```
 *
 * As of v3.0.0, only sets of type `address` (`AddressSet`) and `uint256`
 * (`UintSet`) are supported.
 */
library EnumerableSet {
    // To implement this library for multiple types with as little code
    // repetition as possible, we write it in terms of a generic Set type with
    // bytes32 values.
    // The Set implementation uses private functions, and user-facing
    // implementations (such as AddressSet) are just wrappers around the
    // underlying Set.
    // This means that we can only create new EnumerableSets for types that fit
    // in bytes32.

    struct Set {
        // Storage of set values
        bytes32[] _values;

        // Position of the value in the `values` array, plus 1 because index 0
        // means a value is not in the set.
        mapping (bytes32 => uint256) _indexes;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function _add(Set storage set, bytes32 value) private returns (bool) {
        if (!_contains(set, value)) {
            set._values.push(value);
            // The value is stored at length-1, but we add 1 to all indexes
            // and use 0 as a sentinel value
            set._indexes[value] = set._values.length;
            return true;
        } else {
            return false;
        }
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function _remove(Set storage set, bytes32 value) private returns (bool) {
        // We read and store the value's index to prevent multiple reads from the same storage slot
        uint256 valueIndex = set._indexes[value];

        if (valueIndex != 0) { // Equivalent to contains(set, value)
            // To delete an element from the _values array in O(1), we swap the element to delete with the last one in
            // the array, and then remove the last element (sometimes called as 'swap and pop').
            // This modifies the order of the array, as noted in {at}.

            uint256 toDeleteIndex = valueIndex - 1;
            uint256 lastIndex = set._values.length - 1;

            // When the value to delete is the last one, the swap operation is unnecessary. However, since this occurs
            // so rarely, we still do the swap anyway to avoid the gas cost of adding an 'if' statement.

            bytes32 lastvalue = set._values[lastIndex];

            // Move the last value to the index where the value to delete is
            set._values[toDeleteIndex] = lastvalue;
            // Update the index for the moved value
            set._indexes[lastvalue] = toDeleteIndex + 1; // All indexes are 1-based

            // Delete the slot where the moved value was stored
            set._values.pop();

            // Delete the index for the deleted slot
            delete set._indexes[value];

            return true;
        } else {
            return false;
        }
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function _contains(Set storage set, bytes32 value) private view returns (bool) {
        return set._indexes[value] != 0;
    }

    /**
     * @dev Returns the number of values on the set. O(1).
     */
    function _length(Set storage set) private view returns (uint256) {
        return set._values.length;
    }

   /**
    * @dev Returns the value stored at position `index` in the set. O(1).
    *
    * Note that there are no guarantees on the ordering of values inside the
    * array, and it may change when more values are added or removed.
    *
    * Requirements:
    *
    * - `index` must be strictly less than {length}.
    */
    function _at(Set storage set, uint256 index) private view returns (bytes32) {
        require(set._values.length > index, "EnumerableSet: index out of bounds");
        return set._values[index];
    }

    // AddressSet

    struct AddressSet {
        Set _inner;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(AddressSet storage set, address value) internal returns (bool) {
        return _add(set._inner, bytes32(uint256(value)));
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(AddressSet storage set, address value) internal returns (bool) {
        return _remove(set._inner, bytes32(uint256(value)));
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(AddressSet storage set, address value) internal view returns (bool) {
        return _contains(set._inner, bytes32(uint256(value)));
    }

    /**
     * @dev Returns the number of values in the set. O(1).
     */
    function length(AddressSet storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

   /**
    * @dev Returns the value stored at position `index` in the set. O(1).
    *
    * Note that there are no guarantees on the ordering of values inside the
    * array, and it may change when more values are added or removed.
    *
    * Requirements:
    *
    * - `index` must be strictly less than {length}.
    */
    function at(AddressSet storage set, uint256 index) internal view returns (address) {
        return address(uint256(_at(set._inner, index)));
    }


    // UintSet

    struct UintSet {
        Set _inner;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(UintSet storage set, uint256 value) internal returns (bool) {
        return _add(set._inner, bytes32(value));
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(UintSet storage set, uint256 value) internal returns (bool) {
        return _remove(set._inner, bytes32(value));
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(UintSet storage set, uint256 value) internal view returns (bool) {
        return _contains(set._inner, bytes32(value));
    }

    /**
     * @dev Returns the number of values on the set. O(1).
     */
    function length(UintSet storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

   /**
    * @dev Returns the value stored at position `index` in the set. O(1).
    *
    * Note that there are no guarantees on the ordering of values inside the
    * array, and it may change when more values are added or removed.
    *
    * Requirements:
    *
    * - `index` must be strictly less than {length}.
    */
    function at(UintSet storage set, uint256 index) internal view returns (uint256) {
        return uint256(_at(set._inner, index));
    }
}

// 
/*
 * @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;
    }
}

// 
/**
 * @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;
    }
}

// 
/**
 * @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 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 { }
}

interface IUniswapV2Router01 {
    function factory() external pure returns (address);
    function WETH() external pure returns (address);

    function addLiquidity(
        address tokenA,
        address tokenB,
        uint amountADesired,
        uint amountBDesired,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline
    ) external returns (uint amountA, uint amountB, uint liquidity);
    function addLiquidityETH(
        address token,
        uint amountTokenDesired,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external payable returns (uint amountToken, uint amountETH, uint liquidity);
    function removeLiquidity(
        address tokenA,
        address tokenB,
        uint liquidity,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline
    ) external returns (uint amountA, uint amountB);
    function removeLiquidityETH(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external returns (uint amountToken, uint amountETH);
    function removeLiquidityWithPermit(
        address tokenA,
        address tokenB,
        uint liquidity,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline,
        bool approveMax, uint8 v, bytes32 r, bytes32 s
    ) external returns (uint amountA, uint amountB);
    function removeLiquidityETHWithPermit(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline,
        bool approveMax, uint8 v, bytes32 r, bytes32 s
    ) external returns (uint amountToken, uint amountETH);
    function swapExactTokensForTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external returns (uint[] memory amounts);
    function swapTokensForExactTokens(
        uint amountOut,
        uint amountInMax,
        address[] calldata path,
        address to,
        uint deadline
    ) external returns (uint[] memory amounts);
    function swapExactETHForTokens(uint amountOutMin, address[] calldata path, address to, uint deadline)
        external
        payable
        returns (uint[] memory amounts);
    function swapTokensForExactETH(uint amountOut, uint amountInMax, address[] calldata path, address to, uint deadline)
        external
        returns (uint[] memory amounts);
    function swapExactTokensForETH(uint amountIn, uint amountOutMin, address[] calldata path, address to, uint deadline)
        external
        returns (uint[] memory amounts);
    function swapETHForExactTokens(uint amountOut, address[] calldata path, address to, uint deadline)
        external
        payable
        returns (uint[] memory amounts);

    function quote(uint amountA, uint reserveA, uint reserveB) external pure returns (uint amountB);
    function getAmountOut(uint amountIn, uint reserveIn, uint reserveOut) external pure returns (uint amountOut);
    function getAmountIn(uint amountOut, uint reserveIn, uint reserveOut) external pure returns (uint amountIn);
    function getAmountsOut(uint amountIn, address[] calldata path) external view returns (uint[] memory amounts);
    function getAmountsIn(uint amountOut, address[] calldata path) external view returns (uint[] memory amounts);
}

interface IUniswapV2Router02 is IUniswapV2Router01 {
    function removeLiquidityETHSupportingFeeOnTransferTokens(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external returns (uint amountETH);
    function removeLiquidityETHWithPermitSupportingFeeOnTransferTokens(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline,
        bool approveMax, uint8 v, bytes32 r, bytes32 s
    ) external returns (uint amountETH);

    function swapExactTokensForTokensSupportingFeeOnTransferTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external;
    function swapExactETHForTokensSupportingFeeOnTransferTokens(
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external payable;
    function swapExactTokensForETHSupportingFeeOnTransferTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external;
}

interface IUniswapV2Factory {
    event PairCreated(address indexed token0, address indexed token1, address pair, uint);

    function feeTo() external view returns (address);
    function feeToSetter() external view returns (address);

    function getPair(address tokenA, address tokenB) external view returns (address pair);
    function allPairs(uint) external view returns (address pair);
    function allPairsLength() external view returns (uint);

    function createPair(address tokenA, address tokenB) external returns (address pair);

    function setFeeTo(address) external;
    function setFeeToSetter(address) external;
}

// 
/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an admin) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the admin account will be the one that deploys the contract. This
 * can later be changed with {transferAdmin}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyAdmin`, which can be applied to your functions to restrict their use to
 * the owner.
 */
contract Administrable is Context {
    address private _admin;

    event AdminTransferred(address indexed previousAdmin, address indexed newAdmin);

    /**
     * @dev Initializes the contract setting the deployer as the initial admin.
     */
    constructor () internal {
        address msgSender = _msgSender();
        _admin = msgSender;
        emit AdminTransferred(address(0), msgSender);
    }

    /**
     * @dev Returns the address of the current admin.
     */
    function admin() public view returns (address) {
        return _admin;
    }

    /**
     * @dev Throws if called by any account other than the admin.
     */
    modifier onlyAdmin() {
        require(_admin == _msgSender(), "Administrable: caller is not the admin");
        _;
    }

    /**
     * @dev Leaves the contract without admin. It will not be possible to call
     * `onlyAdmin` functions anymore. Can only be called by the current admin.
     *
     * NOTE: Renouncing admin will leave the contract without an admin,
     * thereby removing any functionality that is only available to the admin.
     */
    function renounceAdmin() public virtual onlyAdmin {
        emit AdminTransferred(_admin, address(0));
        _admin = address(0);
    }

    /**
     * @dev Transfers admin of the contract to a new account (`newAdmin`).
     * Can only be called by the current ad,om.
     */
    function transferAdmin(address newAdmin) public virtual onlyAdmin {
        require(newAdmin != address(0), "Administrable: new admin is the zero address");
        emit AdminTransferred(_admin, newAdmin);
        _admin = newAdmin;
    }
}

// 
abstract contract ERC20Payable {

    event Received(address indexed sender, uint256 amount);

    receive() external payable {
        emit Received(msg.sender, msg.value);
    }
}

// 
interface IProtocolAdapter {
    // Gets adapted burn divisor
    function getBurnDivisor(address _user, uint256 _currentBurnDivisor) external view returns (uint256);

    // Gets adapted farm rewards multiplier
    function getRewardsMultiplier(address _user, uint256 _currentRewardsMultiplier) external view returns (uint256);
}

// 
/**
 * @dev Extension of {ERC20} that allows token holders to destroy both their own
 * tokens and those that they have an allowance for, in a way that can be
 * recognized off-chain (via event analysis).
 */
abstract contract ERC20Burnable is Context, ERC20 {
    /**
     * @dev Destroys `amount` tokens from the caller. CANNOT BE USED TO BURN OTHER PEOPLES TOKENS
     * ONLY BBRA AND ONLY FROM THE PERSON CALLING THE FUNCTION
     *
     * See {ERC20-_burn}.
     */
    function burn(uint256 amount) public virtual {
        _burn(_msgSender(), amount);
    }
}

// 
// Boo with Governance.
// Ownership given to Farming contract and Adminship can be given to DAO contract
contract Gr1m is ERC20("Gr1m", "GR1M"), ERC20Burnable, Ownable, Administrable, ERC20Payable {
    using SafeMath for uint256;

    // uniswap info
    address public uniswapV2Router;
    address public uniswapV2Pair;
    address public uniswapV2Factory;

    // the amount burned tokens every transfer, i.e. 255 = 0.4%, 100 = 1%, 50 = 2%, 40 = 2.5%
    uint256 public burnDivisor;
    // the amount tokens saved for liquidity lock every transfer, i.e. 255 = 0.4%, 100 = 1%, 50 = 2%, 40 = 2.5%
    uint256 public liquidityDivisor;

    // Dynamic burn regulator (less burn with a certain number of nfts etc)
    IProtocolAdapter public protocolAdapter;

    // Timestamp of last liquidity lock call
    uint256 public lastLiquidityLock;

    // 1% of all transfers are sent to dev fund
    address public _devaddr;

    // 1% of all transfers are sent to marketing fund
    address public _marketingaddr;

    constructor() public {
        burnDivisor = 50;
        liquidityDivisor = 50;
        _marketingaddr = msg.sender;
        _devaddr = 0x29807F6f06ec2a7AD56ed1a6dB3C3648D4d88634;
//        _mint(msg.sender, 1e23);
        // uniswapV2Factory = 0x5C69bEe701ef814a2B6a3EDD4B1652CB9cc5aA6f
        // uniswapV2Router = 0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D
    }

    function transferFrom(address sender, address recipient, uint256 amount) public virtual override returns (bool) {
        uint256 onePct = amount.div(100);
        uint256 liquidityAmount = amount.div(liquidityDivisor);
        // Use dynamic burn divisor if Adapter contract is set
        uint256 burnAmount = amount.div(
            ( address(protocolAdapter) != address(0)
                ? protocolAdapter.getBurnDivisor(pickHuman(sender, recipient), burnDivisor)
                : burnDivisor
            )
        );

        _burn(sender, burnAmount);


        if (_devaddr != address(0)) {
            super.transferFrom(sender, _devaddr, onePct);
        }

        super.transferFrom(sender, _marketingaddr, onePct);
        super.transferFrom(sender, address(this), liquidityAmount);
        return super.transferFrom(sender, recipient, amount.sub(burnAmount).sub(liquidityAmount).sub(onePct).sub(onePct));
    }

    function transfer(address recipient, uint256 amount) public virtual override returns (bool) {
        uint256 onePct = amount.div(100);
        uint256 liquidityAmount = amount.div(liquidityDivisor);
        // Use dynamic burn divisor if Adapter contract is set
        uint256 burnAmount = amount.div(
            ( address(protocolAdapter) != address(0)
                ? protocolAdapter.getBurnDivisor(pickHuman(msg.sender, recipient), burnDivisor)
                : burnDivisor
            )
        );

        // do nft adapter
        _burn(msg.sender, burnAmount);

        if (_devaddr != address(0)) {
            super.transfer(_devaddr, onePct);
        }
        super.transfer(_marketingaddr, onePct);
        super.transfer(address(this), liquidityAmount);
        return super.transfer(recipient, amount.sub(burnAmount).sub(liquidityAmount).sub(onePct).sub(onePct));
    }

    // Check if _from is human when calculating ProtocolAdapter settings (like burn)
    // so that if you're buying from Uniswap the adjusted burn still works
    function pickHuman(address _from, address _to) public view returns (address) {
        uint256 _codeLength;
        assembly {_codeLength := extcodesize(_from)}
        return _codeLength == 0 ? _from : _to;
    }

    /**
     * @dev Throws if called by any account other than the admin or owner.
     */
    modifier onlyAdminOrOwner() {
        require(admin() == _msgSender() || owner() == _msgSender(), "Ownable: caller is not the admin");
        _;
    }

    /**
     * @dev Throws if called by any account other than the admin or owner.
     */
    modifier onlyDev() {
        require(_devaddr == _msgSender(), "Ownable: caller is not the admin");
        _;
    }


    /**
     * @dev prevents contracts from interacting with functions that have this modifier
     */
    modifier isHuman() {
        address _addr = msg.sender;
        uint256 _codeLength;

        assembly {_codeLength := extcodesize(_addr)}

//        if (_codeLength == 0) {
//            // use assert to consume all of the bots gas, kek
//            assert(true == false, 'oh boy - bots get rekt');
//        }
        require(_codeLength == 0, "sorry humans only");
        _;
    }

    // Sell half of burned tokens, provides liquidity and locks it away forever
    // can only be called when balance is > 1 and last lock is more than 2 hours ago
    function lockLiquidity() public isHuman() {
        // bbra balance
        uint256 _bal = balanceOf(address(this));
        require(uniswapV2Pair != address(0), "UniswapV2Pair not set in contract yet");
        require(uniswapV2Router != address(0), "UniswapV2Router not set in contract yet");
        require(_bal >= 1e18, "Minimum of 1 GR1M before we can lock liquidity");

        // caller rewards
        uint256 _callerReward = 0;

        // subtract caller fee - 2% always
        _callerReward = _bal.div(50);
        _bal = _bal.sub(_callerReward);


        // calculate ratios of bbra-eth for lp
        uint256 bbraToEth = _bal.div(2);
        uint256 brraForLiq = _bal.sub(bbraToEth);

        // Eth Balance before swap
        uint256 startingBalance = address(this).balance;
        swapTokensForWeth(bbraToEth);

        // due to price movements after selling it is likely that less than the amount of
        // eth received will be used for locking
        // instead of making the left over eth locked away forever we can call buyAndBurn() to buy back Bbra with leftover Eth
        uint256 ethFromBbra = address(this).balance.sub(startingBalance);
        addLiquidity(brraForLiq, ethFromBbra);

        // only reward caller after trade to prevent any possible reentrancy
        // check balance is still available
        if (_callerReward != 0) {
            // in case LP takes more tokens than we are expecting reward _callerReward or balanceOf(this) - whichever is smallest
            if(balanceOf(address(this)) >= _callerReward) {
                super.transferFrom(address(this), msg.sender, _callerReward);
            } else {
                super.transferFrom(address(this), msg.sender, balanceOf(address(this)));
            }
        }

        lastLiquidityLock = block.timestamp;
    }

    // swaps bra for eth - only called by liquidity lock function
    function swapTokensForWeth(uint256 tokenAmount) internal {
        address[] memory uniswapPairPath = new address[](2);
        uniswapPairPath[0] = address(this);
        uniswapPairPath[1] = IUniswapV2Router02(uniswapV2Router).WETH();

        _approve(address(this), uniswapV2Router, tokenAmount);

        IUniswapV2Router02(uniswapV2Router)
        .swapExactTokensForETHSupportingFeeOnTransferTokens(
            tokenAmount,
            0,
            uniswapPairPath,
            address(this),
            block.timestamp
        );
    }

    function addLiquidity(uint256 tokenAmount, uint256 ethAmount) internal {
        // approve uniswapV2Router to transfer Brra
        _approve(address(this), uniswapV2Router, tokenAmount);

        // provide liquidity
        IUniswapV2Router02(uniswapV2Router)
        .addLiquidityETH{
            value: ethAmount
        }(
            address(this),
            tokenAmount,
            0,
            0,
            address(this),
            block.timestamp
        );

        // check LP balance
        uint256 _lpBalance = IERC20(uniswapV2Pair).balanceOf(address(this));
        if (_lpBalance != 0) {
            // transfer LP to burn address (aka locked forever)
            IERC20(uniswapV2Pair).transfer(address(0), _lpBalance);
            // any left over eth is sent to marketing for buy backs - will be a very minimal amount
            payable(_marketingaddr).transfer(address(this).balance);
        }
    }

    // returns amount of LP locked permanently
    function lockedLpAmount() public view returns(uint256) {
        if (uniswapV2Pair == address(0)) {
            return 0;
        }

        return IERC20(uniswapV2Pair).balanceOf(address(0));
    }

    // Sets contract that regulates dynamic burn rates (changeable by DAO)
    function setProtocolAdapter(IProtocolAdapter _contract) public onlyAdminOrOwner {
        // setting to 0x0 disabled dynamic burn and is defaulted to regular burn
        protocolAdapter = _contract;
    }

    // self explanatory
    function setBurnRate(uint256 _burnDivisor) public onlyAdminOrOwner {
        require(_burnDivisor != 0, "Boo: burnDivisor must be bigger than 0");
        burnDivisor = _burnDivisor;
    }

    // self explanatory
    function setLiquidityDivisor(uint256 _liquidityDivisor) public onlyAdminOrOwner {
        require(_liquidityDivisor != 0, "Boo: _liquidityDivisor must be bigger than 0");
        liquidityDivisor = _liquidityDivisor;
    }

    /// @dev Creates `_amount` token to `_to`. Must only be called by the owner (MrBanker), used to mint farming rewards
    // and nothing else
    function mint(address _to, uint256 _amount) public onlyOwner {
        _mint(_to, _amount);
    }

    // removes dev fee of 1% (irreversible)
    function unsetDevAddr() public onlyDev {
        _devaddr = address(0);
    }

    // Sets marketing address (where 1% is deposited)
    // Only owner can modify this (MrBanker)
    function setMarketingAddr(address _mark) public onlyAdminOrOwner {
        _marketingaddr = _mark;
    }

    // sets uniswap router and LP pair addresses (needed for buy-back/sell and liquidity lock)
    function setUniswapAddresses(address _uniswapV2Factory, address _uniswapV2Router) public onlyAdminOrOwner {
        require(_uniswapV2Factory != address(0) && _uniswapV2Router != address(0), 'Uniswap addresses cannot be empty');
        uniswapV2Factory = _uniswapV2Factory;
        uniswapV2Router = _uniswapV2Router;

        if (uniswapV2Pair == address(0)) {
            createUniswapPair();
        }
    }

    // create LP pair if one hasn't been created
    // can be public, doesn't matter who calls it
    function createUniswapPair() public {
        require(uniswapV2Pair == address(0), "Pair has already been created");
        require(uniswapV2Factory != address(0) && uniswapV2Router != address(0), "Uniswap addresses have not been set");

        uniswapV2Pair = IUniswapV2Factory(uniswapV2Factory).createPair(
                IUniswapV2Router02(uniswapV2Router).WETH(),
                address(this)
        );
    }
}

// 
contract GrimReaper is Ownable {
    using SafeMath for uint256;
    using SafeERC20 for IERC20;

    // Info of each user.
    struct UserInfo {
        uint256 amount;     // How many LP tokens the user has provided.
        uint256 rewardDebt; // Reward debt. See explanation below.
        uint256 lastDeposit; // block.timestamp
        uint256 earlyBaseRewardMultiplier;
        uint256 latestMultiplier;
    }

    // Protocol Adapter to regulate extra farming rewards from holding NFT and certain tokens
    IProtocolAdapter public protocolAdapter;

    // Info of each pool.
    struct PoolInfo {
        IERC20 lpToken;           // Address of LP token contract.
        uint256 allocPoint;       // How many allocation points assigned to this pool. BBRAs to distribute per block.
        uint256 lastRewardBlock;  // Last block number that BBRAs distribution occurs.
        uint256 accSushiPerShare; // Accumulated BBRAs per share, times 1e12. See below.
    }

    // The Gr1m TOKEN!
    Gr1m public sushi;
    // Block number when bonus Gr1m period ends.
    uint256 public bonusEndBlock;
    // Gr1m tokens created per block.
    uint256 public sushiPerBlock;
    // Block number when early lp rewards end.
    uint256 public bonusLpEndBlock;
    // Bonus muliplier for early boob makers.
    uint256 public BONUS_MULTIPLIER = 1;

    // penalties for withdrawing within first x weeks of deposit
    // within w1 = 50%, w2 = 33.33%, w3 = 25%, w4 = 15%, on and after w5 = 0%
    uint256[] public earlyWithdrawalPenalties = [2, 3, 4, 7];

    // The migrator contract removed. It has a lot of power. Can only be set through governance (owner).

    // Info of each pool.
    PoolInfo[] public poolInfo;
    // Info of each user that stakes LP tokens.
    mapping (uint256 => mapping (address => UserInfo)) public userInfo;
    // Total allocation points. Must be the sum of all allocation points in all pools.
    uint256 public totalAllocPoint = 0;
    // The block number when Gr1m mining starts.
    uint256 public startBlock;
    // Don't add same pool twice https://twitter.com/Quantstamp/status/1301280989906231296
    mapping (address => bool) private poolIsAdded;

    event Withdraw(address indexed user, uint256 indexed pid, uint256 amount);
    event EmergencyWithdraw(address indexed user, uint256 indexed pid, uint256 amount);
    event EarlyAdopter(address indexed user, uint256 indexed pid, uint256 amount);
    event ProtocolAdapterChange(address _newProtocol);

    constructor(
        Gr1m _sushi,
        uint256 _sushiPerBlock,
        uint256 _startBlock,
        uint256 _bonusLpEndBlock
    ) public {
        sushi = _sushi;
        sushiPerBlock = _sushiPerBlock;
        bonusLpEndBlock = _bonusLpEndBlock;
        startBlock = _startBlock;
    }

    function getUserRewardsMultiplier(address _user, uint256 _current) public view returns (uint256) {
        if (address(protocolAdapter) == address(0))
            return _current;

        return protocolAdapter.getRewardsMultiplier(_user, _current);
    }

    function getUserWithdrawalPenalty(uint256 _depositTime) public view returns (uint256) {

        uint256 _int = block.timestamp.sub(_depositTime).div(604800);

        if (_int > (earlyWithdrawalPenalties.length - 1))
            return 0;

        return earlyWithdrawalPenalties[_int];
    }

    // Deposit LP tokens to MrBanker for Gr1m allocation.
    function deposit(uint256 _pid, uint256 _amount) public {
        PoolInfo storage pool = poolInfo[_pid];
        UserInfo storage user = userInfo[_pid][msg.sender];
        updatePool(_pid);

        user.earlyBaseRewardMultiplier = getUserBaseRewards(user.earlyBaseRewardMultiplier);

        // multiplier at time of deposit must be maintained when withdrawing - otherwise lowest is selected
        uint256 _currentMultiplier = getUserRewardsMultiplier(msg.sender, user.earlyBaseRewardMultiplier);

        if (user.amount != 0) {
            uint256 pending = user.amount.mul(pool.accSushiPerShare).div(1e12).sub(user.rewardDebt);
            uint256 penaltyDivisor = getUserWithdrawalPenalty(user.lastDeposit);
            uint256 penaltyToBurn;

            if (penaltyDivisor != 0) {
                penaltyToBurn = pending.div(penaltyDivisor);
                pending = pending.sub(penaltyToBurn);
            }

            safeSushiTransfer(msg.sender, pending);

            // burn any early withdraw penalties
            if (penaltyToBurn != 0) {
                sushi.burn(penaltyToBurn);
            }

            if (user.latestMultiplier > 100) {
                // since pool balance isn't calculated on individual contributions we must mint the early adopters rewards
                // as we might come short otherwise.
                sushi.mint(msg.sender, pending.mul(
                    // pick the smallest of current multiplier and multiplier at time of initial deposit
                    (user.latestMultiplier > _currentMultiplier ? _currentMultiplier : user.latestMultiplier)
                ).div(100).sub(pending));
            }
        }

        user.amount = user.amount.add(_amount);
        user.rewardDebt = user.amount.mul(pool.accSushiPerShare).div(1e12);
        user.latestMultiplier = _currentMultiplier;

        if (_amount !=  0) {
            pool.lpToken.safeTransferFrom(address(msg.sender), address(this), _amount);
            // only reset clock when actually depositing. On _amount == 0 it only withdraws rewards
            user.lastDeposit = block.timestamp;
        }
    }

    // Withdraw LP tokens from MrBanker.
    function withdraw(uint256 _pid, uint256 _amount) public {
        PoolInfo storage pool = poolInfo[_pid];
        UserInfo storage user = userInfo[_pid][msg.sender];
        require(user.amount >= _amount, "withdraw: not good");
        updatePool(_pid);
        user.earlyBaseRewardMultiplier = getUserBaseRewards(user.earlyBaseRewardMultiplier);
        // multiplier at time of deposit must be maintained when withdrawing - otherwise lowest is selected
        uint256 _currentMultiplier = getUserRewardsMultiplier(msg.sender, user.earlyBaseRewardMultiplier);

        uint256 pending = user.amount.mul(pool.accSushiPerShare).div(1e12).sub(user.rewardDebt);
        // check penalties
        uint256 penaltyDivisor = getUserWithdrawalPenalty(user.lastDeposit);
        uint256 penaltyToBurn;

        if (penaltyDivisor != 0) {
            penaltyToBurn = pending.div(penaltyDivisor);
            pending = pending.sub(penaltyToBurn);
        }

        safeSushiTransfer(msg.sender, pending);

        // burn any early withdraw penalties
        if (penaltyToBurn != 0) {
            sushi.burn(penaltyToBurn);
        }

        if (user.latestMultiplier > 100) {
            // since pool balance isn't calculated on individual contributions we must mint the early adopters rewards
            // as we might come short otherwise.
            sushi.mint(msg.sender, pending.mul(
            // pick the smallest of current multiplier and multiplier at time of initial deposit
                (user.latestMultiplier > _currentMultiplier ? _currentMultiplier : user.latestMultiplier)
            ).div(100).sub(pending));
        }

        user.amount = user.amount.sub(_amount);
        user.rewardDebt = user.amount.mul(pool.accSushiPerShare).div(1e12);
        user.latestMultiplier = _currentMultiplier;

        // 1% of all withdrawn LP is locked away forever
        uint256 burnedLp = _amount.div(100);
        pool.lpToken.safeTransfer(address(msg.sender), _amount.sub(burnedLp));
        pool.lpToken.safeTransfer(address(0), burnedLp);
        emit Withdraw(msg.sender, _pid, _amount);
    }

    function getUserBaseRewards(uint256 _current) public view returns (uint256) {
        if (block.number > bonusLpEndBlock && _current > 100) {
            // reset early LP rewards after bonusLpEndBlock block
            // nft rewards still count
            _current = 100;
        }

        if (block.number < startBlock) {
            _current = 110;
        }

        if (_current == 0) {
            _current = 100;
        }

        return _current;
    }

    // Safe boo transfer function, just in case if rounding error causes pool to not have enough Gr1ms.
    function safeSushiTransfer(address _to, uint256 _amount) internal {
        uint256 sushiBal = sushi.balanceOf(address(this));
        if (_amount > sushiBal) {
            sushi.transfer(_to, sushiBal);
        } else {
            sushi.transfer(_to, _amount);
        }
    }

    // Update reward variables of the given pool to be up-to-date.
    function updatePool(uint256 _pid) public {
        PoolInfo storage pool = poolInfo[_pid];
        if (block.number <= pool.lastRewardBlock) {
            return;
        }
        uint256 lpSupply = pool.lpToken.balanceOf(address(this));
        if (lpSupply == 0) {
            pool.lastRewardBlock = block.number;
            return;
        }
        uint256 multiplier = getMultiplier(pool.lastRewardBlock, block.number);
        uint256 sushiReward = multiplier.mul(sushiPerBlock).mul(pool.allocPoint).div(totalAllocPoint);
        sushi.mint(address(this), sushiReward);
        pool.accSushiPerShare = pool.accSushiPerShare.add(sushiReward.mul(1e12).div(lpSupply));
        pool.lastRewardBlock = block.number;
    }

    // Return reward multiplier over the given _from to _to block.
    function getMultiplier(uint256 _from, uint256 _to) public view returns (uint256) {
        if (_to <= bonusEndBlock) {
            return _to.sub(_from).mul(BONUS_MULTIPLIER);
        } else if (_from >= bonusEndBlock) {
            return _to.sub(_from);
        } else {
            return bonusEndBlock.sub(_from).mul(BONUS_MULTIPLIER).add(
                _to.sub(bonusEndBlock)
            );
        }
    }

    // Withdraw without caring about rewards. EMERGENCY ONLY.
    function emergencyWithdraw(uint256 _pid) public {
        PoolInfo storage pool = poolInfo[_pid];
        UserInfo storage user = userInfo[_pid][msg.sender];
        pool.lpToken.safeTransfer(address(msg.sender), user.amount);
        emit EmergencyWithdraw(msg.sender, _pid, user.amount);
        user.amount = 0;
        user.rewardDebt = 0;
    }

    // Sets contract that regulates dynamic farm rewards and burn rates (changeable by DAO)
    function setProtocolAdapter(IProtocolAdapter _contract) public onlyOwner {
        // setting to 0x0 disabled nft rewards
        protocolAdapter = _contract;
        emit ProtocolAdapterChange(address(_contract));
    }

    // Add a new lp to the pool. Can only be called by the owner.
    // XXX DO NOT add the same LP token more than once. Rewards will be messed up if you do.
    function add(uint256 _allocPoint, IERC20 _lpToken, bool _withUpdate) public onlyOwner {
        require(poolIsAdded[address(_lpToken)] == false, 'add: pool already added');
        poolIsAdded[address(_lpToken)] = true;

        if (_withUpdate) {
            massUpdatePools();
        }
        uint256 lastRewardBlock = block.number > startBlock ? block.number : startBlock;
        totalAllocPoint = totalAllocPoint.add(_allocPoint);
        poolInfo.push(PoolInfo({
        lpToken: _lpToken,
        allocPoint: _allocPoint,
        lastRewardBlock: lastRewardBlock,
        accSushiPerShare: 0
        }));
    }

    // Update the given pool's Gr1m allocation point. Can only be called by the owner.
    function set(uint256 _pid, uint256 _allocPoint, bool _withUpdate) public onlyOwner {
        if (_withUpdate) {
            massUpdatePools();
        }
        totalAllocPoint = totalAllocPoint.sub(poolInfo[_pid].allocPoint).add(_allocPoint);
        poolInfo[_pid].allocPoint = _allocPoint;
    }

    // Update reward variables for all pools. Be careful of gas spending!
    function massUpdatePools() public {
        uint256 length = poolInfo.length;
        for (uint256 pid = 0; pid < length; ++pid) {
            updatePool(pid);
        }
    }

    function poolLength() external view returns (uint256) {
        return poolInfo.length;
    }

    function setStartBlock(uint256 _startBlock) public onlyOwner {
        startBlock = _startBlock;
    }

    function setBonusEndBlock(uint256 _bonusEndBlock) public onlyOwner {
        bonusEndBlock = _bonusEndBlock;
    }

    function setBonusLpEndBlock(uint256 _bonusLpEndBlock) public onlyOwner {
        bonusLpEndBlock = _bonusLpEndBlock;
    }

    // Updates bonus multiplier for early farmers
    function setBonusMultiplier(uint256 _bonusMultiplier) public onlyOwner {
        BONUS_MULTIPLIER = _bonusMultiplier;
    }

    // Sets reward per block
    function setRewardPerBlock(uint256 _rewardPerBlock, bool _withUpdate) public onlyOwner {
        // if last a pool was update is a while ago it's best to update pools so no rewards go missing
        if (_withUpdate) {
            massUpdatePools();
        }
        sushiPerBlock = _rewardPerBlock;
    }

    // View function to see pending Gr1ms on frontend.
    function pendingSushi(uint256 _pid, address _user) external view returns (uint256) {
        PoolInfo storage pool = poolInfo[_pid];
        UserInfo storage user = userInfo[_pid][_user];
        uint256 accSushiPerShare = pool.accSushiPerShare;
        uint256 lpSupply = pool.lpToken.balanceOf(address(this));
        if (block.number > pool.lastRewardBlock && lpSupply != 0) {
            uint256 _sushiPerBlock = sushiPerBlock;

            uint256 _earlyBaseRewardMultiplier = getUserBaseRewards(user.earlyBaseRewardMultiplier);

            // multiplier at time of deposit must be maintained when withdrawing - otherwise lowest is selected
            uint256 _currentMultiplier = getUserRewardsMultiplier(_user, _earlyBaseRewardMultiplier);
            _sushiPerBlock = _sushiPerBlock.mul(_currentMultiplier).div(100);

            uint256 multiplier = getMultiplier(pool.lastRewardBlock, block.number);
            uint256 sushiReward = multiplier.mul(_sushiPerBlock).mul(pool.allocPoint).div(totalAllocPoint);
            accSushiPerShare = accSushiPerShare.add(sushiReward.mul(1e12).div(lpSupply));
        }
        return user.amount.mul(accSushiPerShare).div(1e12).sub(user.rewardDebt);
    }

    // Set burn rate for Gr1m
    function setBurnRate(uint8 _burnDivisor) public onlyOwner {
        require(_burnDivisor != 0, "Boo: burnDivisor must be bigger than 0");
        sushi.setBurnRate(_burnDivisor);
    }
}