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: physical activity 
Words: tumble, summer, fall, bend, lift
Example Output: summer

Example Input: Category: elements 
Words: ban, fire, combustion, ground, flame
Example Output: ban

Example Input: Category: food 
Words: hot dog, blunt, frank, goodies, vittles
Example Output:
blunt