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: bike, flap, fly, walk, wave
Example Output: walk

Example Input: prison, mad, arrest, fine, wispy
Example Output: mad

Example Input: windy, brisk, mild, trustworthy, fair
Example Output:
trustworthy