Dr. Wayne has a new way to do open addressing, where, for a key k, if the cell h(k) is occupied, then he suggests trying (h(k) + i · f(k)) mod N, for i = 1, 2, 3,..., until finding an empty cell, where f(k) is a random hash function returning values from 1 to N − 1. Explain what can go wrong with Dr. Wayne’s scheme if N is not prime.