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: fire, retire, ice, air, earth

Ex Output:
retire


Ex Input:
Category: nutritional value 
Words: vitamin c, salt, sugar, fat, big boned

Ex Output:
big boned


Ex Input:
Category: guitar part 
Words: amp, fret, board, truss rod, concerned

Ex Output:

concerned