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: bird 
Words: ostrich, digger, sandpiper, crane, goose
Example Output: digger

Example Input: Category: secretary duty 
Words: errands, fax, file, type, ram
Example Output: ram

Example Input: Category: bird 
Words: tackle, parrot, duck, crane, davit
Example Output:
tackle