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: animal 
Words: pounce, fly, swim, walk, walk
Example Output: walk

Example Input: Category: computers 
Words: prepare, space, file, image, ram
Example Output: prepare

Example Input: Category: social gathering 
Words: dance hall, meeting, toast, group, club
Example Output:
toast