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: dangle, wave, eagle, fly, leap
Example Output: wave

Example Input: windlass, hummingbird, neck, crane, duck
Example Output: windlass

Example Input: cool, persistent, assured, ethical, tropical
Example Output:
tropical