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: body part 
Words: foot, knee, eye, leg, ounce
Example Output: ounce

Example Input: Category: bird 
Words: goose, hoist, neck, swallow, crane
Example Output: hoist

Example Input: Category: type of sandwich 
Words: submarine, group, club, roll, grilled cheese
Example Output:
group