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:
recruit, replace, sack, heat, fire

Ex Output:
heat


Ex Input:
format, file, support, text, download

Ex Output:
support


Ex Input:
water, current, history, flow, tide

Ex Output:

history