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: bird 
Words: winch, swallow, winch, crane, parrot
Example Output: winch

Example Input: Category: ocean 
Words: current, data sets, main, sea, wave
Example Output: data sets

Example Input: Category: boats 
Words: rudder, gunwale, caution, deck, lifeline
Example Output:
caution