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: animal 
Words: pounce, fly, swim, walk, walk

Ex Output:
walk


Ex Input:
Category: emotional status 
Words: kind, down, sad, backward, emotionalities

Ex Output:
backward


Ex Input:
Category: employment activity 
Words: fire, recruit, air, retire, empower

Ex Output:

air