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:
townhome, mountain, studio, flat, apartment

Ex Output:
mountain


Ex Input:
valley, house, cabin, squashed, flat

Ex Output:
valley


Ex Input:
answer calls, answer, file, firewall, support

Ex Output:

firewall