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.

Example Input: vitamin c, carbs, fiber, fat, thin
Example Output: thin

Example Input: sustainability, firm, amalgamated, combined, rigged
Example Output: rigged

Example Input: thin, brittleness, heavy, angular momentum, fat
Example Output:
heavy