Given the task definition, example input & output, solve the new input case.
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: Category: construction 
Words: excavator, crane, pelican, hoist, upraise
Output: pelican
A pelican is not related to construction because it is a type of bird.

New input case for you: Category: employment activity 
Words: heat, fire, empower, hire, replace
Output:
heat