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: type of rigidity 
Words: tough, taut, rough, amalgamated, firm

Ex Output:
amalgamated


Ex Input:
Category: bird 
Words: swift, tackle, pelican, crane, hoist

Ex Output:
hoist


Ex Input:
Category: bird 
Words: concrete pourer, swift, crane, hoist, parrot

Ex Output:

concrete pourer