Hello HeartStorm907
Before I start I will make it very clear that I have not looked at question or answer properly.
I will also say that I have NEVER said it is ok to post AoPS questions, especially when you are just looking for the answer.
Why do I think you are just after the answer?
Becasue you did not notice that originally key elements of the questin were missing.
AND more importantly
Because you just told CPhill his long answer was 'wrong'
It is easy to have a fundamentally correct answer but due to some small error somewhere the last line could be incorrect.
Did you look at CPhill's working? Or did you just plug in the last line and dismiss all he had done for you.
I never saw a thankyou anywhere. (for his time and effort)
Nor did I see you ask for any clarification of his working.