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.

Example Input: forward, opposite of up, unhappy, downward, down
Example Output: unhappy

Example Input: cards, deck, suits, box, fold
Example Output: box

Example Input: impartial, equitable, fair, unprejudiced, mild
Example Output:
mild