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: boxing terminology 
Words: glove, level, deck, corner, board
Example Output: board

Example Input: Category: secretary duty 
Words: fax, program, file, make coffee, answer
Example Output: program

Example Input: Category: employment activity 
Words: hire, heat, fire, retire, ban
Example Output:
heat