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: employment activity 
Words: fire, hire, ground, pay, retire
Example Output: ground

Example Input: Category: police punishment 
Words: prime, penalty, fine, mad, arrest
Example Output: mad

Example Input: Category: police punishment 
Words: flyaway, prime, high quality, fine, jail time
Example Output:
high quality