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.

Input: Consider Input: Category: employment activity 
Words: ban, fire, empower, sack, ground

Output: ground


Input: Consider Input: Category: measurement unit 
Words: ounce, foot, kilometer, milimeter, heel

Output: heel


Input: Consider Input: Category: type of rigidity 
Words: unbending, unyielding, inflexible, firm, streamline


Output: streamline