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: secretary duty 
Words: schedule, file, answer calls, correspondence, ram
Example Output: ram

Example Input: Category: activity 
Words: fritter, waste, pie, waste away, lollygag
Example Output: pie

Example Input: Category: window material 
Words: panel, glass, vinyl, wood, cup
Example Output:
cup