	function transferFrom(address _from, address _to, uint _value) public {
	    require(balances[_from] >= _value && allowed[_from][msg.sender] >= _value && _value > 0);
            balances[_to] = balances[_to].add(_value);
            balances[_from] = balances[_from].sub(_value);
            allowed[_from][msg.sender] = allowed[_from][msg.sender].sub(_value);
            emit Transfer(_from, _to, _value);
    }