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:
dump truck, tackle, crane, duck, mallet

Ex Output:
dump truck

Ex Input:
fearful, content, substance, program, thing

Ex Output:
fearful

Ex Input:
fold, pack, rudder, blind, deck

Ex Output:
rudder