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: police punishment 
Words: wispy, fine, probation, calm, prime
Example Output: calm

Example Input: Category: baby animals 
Words: follow, colt, fawn, cub, calf
Example Output: follow

Example Input: Category: boats 
Words: galley, deck, hull, head, pack
Example Output:
pack