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:
streamline, sustainability, private, firm, stiff

Ex Output:
stiff


Ex Input:
provision, frank, hot dog, goodies, harsh

Ex Output:
harsh


Ex Input:
dull, happy, beautiful, level, fine

Ex Output:

happy