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: fine, prime, arrest, hot, jail time
Example Output: hot

Example Input: synergy, solid, firm, amalgamated, sustainability
Example Output:
solid