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: physical activity 
Words: drop, fall, leaves, bend, exercise

Output: leaves


Input: Consider Input: Category: elements 
Words: ground, replace, combustion, flame, fire

Output: replace


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


Output: digger