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 sandwich 
Words: club, open-faced, convention, doorstep, roll

Ex Output:
convention


Ex Input:
Category: window material 
Words: glass, spyhole, handle, coating, knive

Ex Output:
knive


Ex Input:
Category: bird 
Words: swallow, duck, winch, heron, crane

Ex Output:

winch