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: guitar part 
Words: truss rod, fret, neck, bored, strap lock

Ex Output:
bored


Ex Input:
Category: physical property 
Words: fat, angular momentum, ugly, capacitance, fiber

Ex Output:
fiber


Ex Input:
Category: emotional status 
Words: kind, down, sad, backward, emotionalities

Ex Output:

backward