Given a set of five words, generate the word from the set that does not belong (i.e. is the least relevant) with the other words. Words are separated by commas.

Ex Input:
happy, substance, shop, tools, content

Ex Output:
happy


Ex Input:
unflappalbe, refreshing, funny, cool, confident

Ex Output:
refreshing


Ex Input:
falling, backward, left, disgusted, down

Ex Output:

disgusted