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: hull, galley, deck, lifeline, tko
Example Output: tko

Example Input: brash, frank, bun, hot dog, grub
Example Output: brash

Example Input: glass, acrylic, wood, coating, cup
Example Output:
cup