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.

Input: Consider Input: townhome, mountain, studio, flat, apartment

Output: mountain

Input: Consider Input: summer, roll, plummet, fall, exercise

Output: summer

Input: Consider Input: heron, tackle, hummingbird, crane, hoist
Output: tackle