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: mode of transportation
Words: train, spider, wave, fly, drive
Example Output: spider

Example Input: Category: activity
Words: spend, divide, apple, whittle, fritter
Example Output: apple

Example Input: Category: animals
Words: geese, jog, swan, duck, horse
Example Output:
jog