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.
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Question: Category: elements 
Words: pay, cool, combustion, air, fire

Answer: pay


Question: Category: poker 
Words: ring, deck, blind, cards, joker

Answer: ring


Question: Category: nutritional value 
Words: calcium, heavy, fat, sugar, pasty

Answer:
pasty