[math-fun] Brushing your teeth with Pascal's triangle

I was surprised to see this puzzle on the back of my milk carton today at breakfast: http://lunkwill.org/tmp/pascal.jpg The fine print says to check smartcarton.com for problem #M027 to see the answer. Entering "027" turns up a different pyramid-shaped problem, though. In any case, I'm going to have trouble getting much done today if I have to brush my teeth 33 times.