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: hamster, mice, fish, tiger, row
Example Output: row

Example Input: Category: social gathering 
Words: convention, club, discothek, hamburger, dance hall
Example Output: hamburger

Example Input: Category: direction 
Words: down, downward, opposite of up, ground, loveful
Example Output:
loveful