That's a very good question and the answer is the number of molecules you can count that makes up Twilight Sparkle's butt. You might have guess that Twilight Sparkle actually counts molecules on her butt. Yes she does.
Q: What's my best feature, my face or my butt?
Hahahahahahah my stupid young fellow. Of course you do! In our hearts. Specifically in the hearts of a thousand child elbows.
Q: What does P P did to U U if it O O?
From Urban Dictionary: Nature's way of tricking people into reproducing.
Q: What are pine cones? Are they Pineapples on cones? Or are they Cone flavored pineapples?