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: type of rigidity 
Words: inflexible, tough, taut, firm, leverage

Ex Output:
leverage


Ex Input:
Category: moral characteristic 
Words: frank, stern, bun, concise, precise

Ex Output:
bun


Ex Input:
Category: secretary duty 
Words: schedule appointments, download, organize, correspondence, file

Ex Output:

download