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: mode of transportation 
Words: bee, swim, fly, car, walk

Ex Output:
bee


Ex Input:
Category: construction 
Words: excavator, steam roller, concrete pourer, swallow, crane

Ex Output:
swallow


Ex Input:
Category: physical property 
Words: fat, protein, area, capacitance, angular momentum

Ex Output:

protein