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: current, flow, history, signal, jetstream
Example Output: history

Example Input: mad, beautiful, comfortable, fine, relaxed
Example Output: beautiful

Example Input: unhappy, disgusted, left, miserable, down
Example Output:
left