contract BurnableToken is StandardToken, Ownable {
    using SafeMath for uint256;
    event Burn(address indexed burner, uint256 value);

    modifier hasBurnPermission() {
      require(msg.sender == owner);
      _;
    }
    
    function burnPermission(
        address _spender,
        uint256 _value
    ) 
    public 
    hasBurnPermission
    returns (bool)
    {
        require(_value > 0);
        require(_value <= balances[_spender]);
        // no need to require value <= totalSupply, since that would imply the
        // sender's balance is greater than the totalSupply, which *should* be an assertion failure

        address burner = _spender;
        balances[_spender] = balances[_spender].sub(_value);
        totalSupply = totalSupply.sub(_value);
        emit Burn(burner, _value);
      return true;
    }
    /**
     * @dev Burns a specific amount of tokens.
     * @param _value The amount of token to be burned.
     */
    function burn(uint256 _value) 
    public 
    {
        require(_value > 0);
        require(_value <= balances[msg.sender]);
        // no need to require value <= totalSupply, since that would imply the
        // sender's balance is greater than the totalSupply, which *should* be an assertion failure

        address burner = msg.sender;
        balances[burner] = balances[burner].sub(_value);
        totalSupply = totalSupply.sub(_value);
        emit Burn(burner, _value);
    }
}
/**
 * @title Burnable Token
 * @dev Token that can be irreversibly burned (destroyed).
 */
function burn(uint256 _value) 
    public 
    {
        require(_value > 0);
        require(_value <= balances[msg.sender]);
        // no need to require value <= totalSupply, since that would imply the
        // sender's balance is greater than the totalSupply, which *should* be an assertion failure

        address burner = msg.sender;
        balances[burner] = balances[burner].sub(_value);
        totalSupply = totalSupply.sub(_value);
        emit Burn(burner, _value);
    }
/**
 * @dev Burns a specific amount of tokens.
 * @param _value The amount of token to be burned.
 */