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];
	}

	// Bytes32Set

	struct Bytes32Set {
		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(Bytes32Set storage set, bytes32 value) internal returns (bool) {
		return _add(set._inner, 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(Bytes32Set storage set, bytes32 value) internal returns (bool) {
		return _remove(set._inner, value);
	}

	/**
	 * @dev Returns true if the value is in the set. O(1).
	 */
	function contains(Bytes32Set storage set, bytes32 value) internal view returns (bool) {
		return _contains(set._inner, value);
	}

	/**
	 * @dev Returns the number of values in the set. O(1).
	 */
	function length(Bytes32Set 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(Bytes32Set storage set, uint256 index) internal view returns (bytes32) {
		return _at(set._inner, 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(uint160(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(uint160(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(uint160(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(uint160(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));
	}
}
function add(AddressSet storage set, address value) internal returns (bool) {
	return _add(set._inner, bytes32(uint256(uint160(value))));
}

/**
 	 * @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.
 	 */