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: elephant, duck, sprint, dog, lion
Example Output: sprint

Example Input: emotional state, opposite of up, unhappy, down, miserable
Example Output: opposite of up

Example Input: level, fine, penalty, bright, neat
Example Output:
penalty