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: trustworthy, decent, fair, tone, ok
Example Output: tone

Example Input: fat, calories, thin, salt, vitamin c
Example Output: thin

Example Input: flat, emotional upsets, down, sliding, falling
Example Output:
emotional upsets