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: outdoor sport activity 
Words: dog, swim, hike, hiking, fish
Example Output: dog

Example Input: Category: bird 
Words: dump truck, pelican, goose, crane, derrick
Example Output: dump truck

Example Input: Category: emotional display 
Words: identity, follow, fawn, calf, suppressed
Example Output:
calf