Please don't shoot if this is in the wrong section. I'm pretty sure its not, but I've said that before. I think it should go in this section because its actually an algebraic sum.. right?

Anyway. I've got this problem:

A polygon with sides has a total of diagonals, where and are integers.

Find the values of and .

I don't know what to do! There are no integers in the sum to start with...