Given a set of five words, generate the word from the set that does not belong (i.e. is the least relevant) with the other words. Words are separated by commas.

Ex Input:
bow, duck, sheep, goose, geese

Ex Output:
bow

Ex Input:
deal, fair, endure, windy, ghostly

Ex Output:
ghostly

Ex Input:
regular, universal, general, ubiquitous, private

Ex Output:
private