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.

Example Input: Category: aesthetic characteristic 
Words: 70, variety, color, fair, light
Example Output: 70

Example Input: Category: physical property 
Words: ugly, protein, large, heavy, fat
Example Output: protein

Example Input: Category: physical activity 
Words: sprint, swim, jog, duck, elephant
Example Output:
elephant