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: employment activity 
Words: ban, fire, empower, sack, ground

Ex Output:
ground


Ex Input:
Category: ocean 
Words: current, data sets, main, sea, wave

Ex Output:
data sets


Ex Input:
Category: corporate 
Words: tough, common, firm, alignment, combined

Ex Output:

tough