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: aesthetic characteristic 
Words: there, ticket, fine, dull, level
Example Output: ticket

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

Example Input: Category: boxing terminology 
Words: canvas, sail, level, blocking, deck
Example Output:
sail