contract AccessControl {
    /// @dev The addresses of the accounts (or contracts) that can execute actions within each roles
    address public ceoAddress;
    address public cooAddress;

    /// @dev Keeps track whether the contract is paused. When that is true, most actions are blocked
    bool public paused = false;

    /// @dev The AccessControl constructor sets the original C roles of the contract to the sender account
    function AccessControl() public {
        ceoAddress = msg.sender;
        cooAddress = msg.sender;
    }

    /// @dev Access modifier for CEO-only functionality
    modifier onlyCEO() {
        require(msg.sender == ceoAddress);
        _;
    }

    /// @dev Access modifier for COO-only functionality
    modifier onlyCOO() {
        require(msg.sender == cooAddress);
        _;
    }

    /// @dev Access modifier for any CLevel functionality
    modifier onlyCLevel() {
        require(msg.sender == ceoAddress || msg.sender == cooAddress);
        _;
    }

    /// @dev Assigns a new address to act as the CEO. Only available to the current CEO
    /// @param _newCEO The address of the new CEO
    function setCEO(address _newCEO) public onlyCEO {
        require(_newCEO != address(0));
        ceoAddress = _newCEO;
    }

    /// @dev Assigns a new address to act as the COO. Only available to the current CEO
    /// @param _newCOO The address of the new COO
    function setCOO(address _newCOO) public onlyCEO {
        require(_newCOO != address(0));
        cooAddress = _newCOO;
    }

    /// @dev Modifier to allow actions only when the contract IS NOT paused
    modifier whenNotPaused() {
        require(!paused);
        _;
    }

    /// @dev Modifier to allow actions only when the contract IS paused
    modifier whenPaused {
        require(paused);
        _;
    }

    /// @dev Pause the smart contract. Only can be called by the CEO
    function pause() public onlyCEO whenNotPaused {
        paused = true;
    }

    /// @dev Unpauses the smart contract. Only can be called by the CEO
    function unpause() public onlyCEO whenPaused {
        paused = false;
    }
}
// inspired by
// https://github.com/axiomzen/cryptokitties-bounty/blob/master/contracts/KittyAccessControl.sol
function pause() public onlyCEO whenNotPaused {
    paused = true;
}

/// @dev Pause the smart contract. Only can be called by the CEO