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: corporate 
Words: solid, sustainability, streamline, firm, private
Example Output: solid

Example Input: Category: emotional status 
Words: left, emotional state, sad, emotional upsets, down
Example Output: left

Example Input: Category: emotional status 
Words: annoyed, wispy, ok, fine, comfortable
Example Output:
wispy