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:
firm, tough, solid, hard, streamline

Ex Output:
streamline


Ex Input:
specialty, content, angry, program, activity

Ex Output:
angry


Ex Input:
apartment, cabin, flat, round, valley

Ex Output:

valley