Well, I'm one of the musically inclined, and I'm not too sure on that either, so don't feel too bad.
I learned it at one point, when I was still taking piano lessons...so, O Mitya, does the interval include both the lower and higher notes, or just one? In other words, is C to E a second or third?
Mmf. I should be, like, getting to sleep at some point. Oh well.
Ich bin eine faule Zwiebel.