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.

Ex Input:
Category: elements 
Words: ban, fire, combustion, ground, flame

Ex Output:
ban


Ex Input:
Category: employment activity 
Words: fire, hire, ground, pay, retire

Ex Output:
ground


Ex Input:
Category: emotional status 
Words: detached, relaxed, penalty, ok, fine

Ex Output:

penalty