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:
clothing, content, service, substance, ecstatic

Ex Output:
ecstatic


Ex Input:
check, stern, hull, galley, deck

Ex Output:

check