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: activity 
Words: blow, waste away, sweet roll, whittle, fritter
Example Output: sweet roll

Example Input: Category: bird 
Words: winch, swallow, winch, crane, parrot
Example Output: winch

Example Input: Category: physical activity 
Words: swim, fall, cold, tumble, climb
Example Output:
cold