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, timely, prompt, drink, do tests
Example Output: drink

Example Input: prime, penalty, fine, mad, arrest
Example Output: mad

Example Input: cockroach, fly, train, car, glide
Example Output:
cockroach