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:
sustainability, firm, amalgamated, combined, rigged

Ex Output:
rigged


Ex Input:
lower, backward, down, falling, shameful

Ex Output:
shameful


Ex Input:
burn, replace, empower, retire, fire

Ex Output:

burn