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: aesthetic characteristic 
Words: size, alright, even, variety, fair
Example Output: alright

Example Input: Category: measurement unit 
Words: ounce, ear, inch, foot, milimeter
Example Output: ear

Example Input: Category: social gathering 
Words: club, outing, clan, group, hero
Example Output:
hero