Given a category and a set of five words, find the word from the set that does not belong (i.e. is the least relevant) with the other words in the category. Words are separated by commas.

Example Input: Category: boxing terminology 
Words: caution, hearts, canvas, deck, fight
Example Output: hearts

Example Input: Category: physical activity 
Words: run, jump, autumn, fall, swim
Example Output: autumn

Example Input: Category: animal 
Words: spider, run, waggle, fly, bike
Example Output:
bike