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: condominium, duplex, studio, flat, level
Example Output: level

Example Input: parrot, goose, crane, swallow, excavator
Example Output: excavator

Example Input: history, brine, tide, water, current
Example Output:
history