contract StandardToken is ERC20, Pausable {
	
    using SafeMath for uint256;
    
    mapping(address => uint256) balances;
    
    mapping(address => mapping(address => uint256)) internal allowed;
    
    uint256 totalSupply_;
    
  	/**
     * @dev Total number of tokens in existence
     */
  	function totalSupply() public view returns (uint256) {
    	return totalSupply_;
  	}    
    
  	/**
  	 * @dev Gets the balance of the specified address.
  	 * @param _owner The address to query the the balance of.
  	 * @return An uint256 representing the amount owned by the passed address.
  	 */    
    function balanceOf(address _owner) public view returns (uint256) {
        return balances[_owner];
    }
    
  	/**
   	 * @dev Function to check the amount of tokens that an owner allowed to a spender.
   	 * @param _owner address The address which owns the funds.
   	 * @param _spender address The address which will spend the funds.
   	 * @return A uint256 specifying the amount of tokens still available for the spender.
   	 */    
    function allowance(address _owner, address _spender) public view whenNotPaused returns (uint256) {
        return allowed[_owner][_spender];
    }
    
  	/**
  	 * @dev Transfer token for a specified address
  	 * @param _to The address to transfer to.
  	 * @param _value The amount to be transferred.
  	 */    
    function transfer(address _to, uint256 _value) public whenNotPaused returns (bool) {
    	require(_value <= balances[msg.sender]);
    	require(_to != address(0));
    
        balances[msg.sender] = balances[msg.sender].sub(_value);
        balances[_to] = balances[_to].add(_value);
        emit Transfer(msg.sender, _to, _value);
        return true;
    }

  	/**
   	 * @dev Approve the passed address to spend the specified amount of tokens on behalf of msg.sender.
   	 * 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
   	 * @param _spender The address which will spend the funds.
   	 * @param _value The amount of tokens to be spent.
   	 */
    function approve(address _spender, uint256 _value) public whenNotPaused returns (bool) {
        allowed[msg.sender][_spender] = _value;
        emit Approval(msg.sender, _spender, _value);
        return true;
    }

  	/**
   	 * @dev Transfer tokens from one address to another
   	 * @param _from address The address which you want to send tokens from
   	 * @param _to address The address which you want to transfer to
   	 * @param _value uint256 the amount of tokens to be transferred
   	 */
    function transferFrom(address _from, address _to, uint256 _value) public whenNotPaused returns (bool) {
	    require(_value <= balances[_from]);
	    require(_value <= allowed[_from][msg.sender]);
	    require(_to != address(0));    	

        balances[_from] = balances[_from].sub(_value);
        balances[_to] = balances[_to].add(_value);
        allowed[_from][msg.sender] = allowed[_from][msg.sender].sub(_value);
        emit Transfer(_from, _to, _value);
        return true;
    }

	/**
   	 * @dev Increase the amount of tokens that an owner allowed to a spender.
   	 * approve should be called when allowed[_spender] == 0. To increment
   	 * allowed value is better to use this function to avoid 2 calls (and wait until
   	 * the first transaction is mined)
   	 * From MonolithDAO Token.sol
   	 * @param _spender The address which will spend the funds.
   	 * @param _addedValue The amount of tokens to increase the allowance by.
   	 */
    function increaseApproval(address _spender, uint256 _addedValue) public whenNotPaused returns (bool) {
        allowed[msg.sender][_spender] = allowed[msg.sender][_spender].add(_addedValue);
        emit Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
        return true;
    }

  	/**
   	 * @dev Decrease the amount of tokens that an owner allowed to a spender.
   	 * approve should be called when allowed[_spender] == 0. To decrement
   	 * allowed value is better to use this function to avoid 2 calls (and wait until
   	 * the first transaction is mined)
   	 * From MonolithDAO Token.sol
   	 * @param _spender The address which will spend the funds.
   	 * @param _subtractedValue The amount of tokens to decrease the allowance by.
   	 */
    function decreaseApproval(address _spender, uint256 _subtractedValue) public whenNotPaused returns (bool) {
    	uint256 oldValue = allowed[msg.sender][_spender];
        if (_subtractedValue >= oldValue) {
            allowed[msg.sender][_spender] = 0;
        } else {
            allowed[msg.sender][_spender] = oldValue.sub(_subtractedValue);
        }

        emit Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
        return true;
    }

  	/**
   	 * @dev Decrease the amount of tokens that an owner allowed to a spender by spender self.
   	 * approve should be called when allowed[msg.sender] == 0. To decrement
   	 * allowed value is better to use this function to avoid 2 calls (and wait until
   	 * the first transaction is mined)
   	 * From MonolithDAO Token.sol
   	 * @param _from The address which will transfer the funds from.
   	 * @param _subtractedValue The amount of tokens to decrease the allowance by.
   	 */
    function spenderDecreaseApproval(address _from, uint256 _subtractedValue) public whenNotPaused returns (bool) {
    	uint256 oldValue = allowed[_from][msg.sender];
        if (_subtractedValue >= oldValue) {
            allowed[_from][msg.sender] = 0;
        } else {
            allowed[_from][msg.sender] = oldValue.sub(_subtractedValue);
        }

        emit Approval(_from, msg.sender, allowed[_from][msg.sender]);
        return true;
    }
}
/**
 * @title Standard ERC20 token
 *
 * @dev Implementation of the basic standard token.
 * https://github.com/ethereum/EIPs/issues/20
 */
function decreaseApproval(address _spender, uint256 _subtractedValue) public whenNotPaused returns (bool) {
	uint256 oldValue = allowed[msg.sender][_spender];
    if (_subtractedValue >= oldValue) {
        allowed[msg.sender][_spender] = 0;
    } else {
        allowed[msg.sender][_spender] = oldValue.sub(_subtractedValue);
    }

    emit Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
    return true;
}

/**
 	 * @dev Decrease the amount of tokens that an owner allowed to a spender.
 	 * approve should be called when allowed[_spender] == 0. To decrement
 	 * allowed value is better to use this function to avoid 2 calls (and wait until
 	 * the first transaction is mined)
 	 * From MonolithDAO Token.sol
 	 * @param _spender The address which will spend the funds.
 	 * @param _subtractedValue The amount of tokens to decrease the allowance by.
 	 */