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: personal characteristic 
Words: ethical, tropical, unflappalbe, cool, optimist

Output: tropical


Input: Consider Input: Category: bird 
Words: ostrich, digger, sandpiper, crane, goose

Output: digger


Input: Consider Input: Category: direction 
Words: right, down, downward, up, kind


Output: kind