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: errands, schedule appointments, image, make coffee, file
Example Output: image

Example Input: Category: food 
Words: sausage, loyalty, grub, frank, provision
Example Output: loyalty

Example Input: Category: construction 
Words: digger, concrete pourer, crane, derrick, excavator
Example Output:
derrick