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: elements 
Words: ground, replace, combustion, flame, fire

Ex Output:
replace


Ex Input:
Category: activity 
Words: blow, waste away, sweet roll, whittle, fritter

Ex Output:
sweet roll


Ex Input:
Category: animal 
Words: fly, swim, waggle, dive, wave

Ex Output:

wave