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.

Ex Input:
Category: geographical property 
Words: mountain, flat, hill, mansion, plain

Ex Output:
mansion


Ex Input:
Category: weather 
Words: luke, equitable, clime, fair, mild

Ex Output:
equitable


Ex Input:
Category: bird 
Words: winch, egret, crane, digger, neck

Ex Output:

digger