There are $6$ orange, $10$ yellow, $4$ pink and $12$ brown shirts in the closet. At least how many shirts must Annabella take out the closet to get $$1$$ yellow shirt for sure? 
Overseas Competition->Knowledge Point->Combinatorics->Pigeonhole Principle->Worst Case in Pigeonhole Principle Problems Overseas Competition->Knowledge Point->Counting Modules->Permutations and Combinations->Combinations