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: fine, prime, firstrate, custody, ok
Example Output: ok

Example Input: fire, instruct, inferno, retire, scold
Example Output: inferno

Example Input: file, space, program, firewall, answer
Example Output:
answer