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:
apartment, round, valley, flat, even

Ex Output:
valley


Ex Input:
neat, beautiful, dull, fine, firstrate

Ex Output:
firstrate


Ex Input:
deck, fight, fold, knockout, punch

Ex Output:

fold