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: fire, retire, ice, air, earth

Ex Output:
retire


Ex Input:
Category: window material 
Words: panel, translucent fabric, spatula, metal, glass

Ex Output:
spatula


Ex Input:
Category: consumer product 
Words: joyful, specialty, merchandise, content, service

Ex Output:

joyful