Finally, let's balance the oxygen out. So notice we have two times two oxygens. So four oxygen here, and three times one oxygen, three oxygens here. So we have a total of seven oxygens here. That means we have to multiply this guy by seven over two, because seven over two times two, the twos cancel and we are left with seven oxygen molecules here. So, in other words, we put in two carbons, six HS, and seven OS, and we get back two carbons, six H's, and three times one, two times four, seven O's.