Given a natural number N. Determine if it is prime. A natural number N is called prime if it has only two divisors: one and the number N itself. As an answer, print "Yes" if the number is prime, "No" otherwise.

def is_prime(num):
  if num < 2:
    return False
  for i in range(2, num):
    if num % i == 0:
      return False
  return True

is_prime(3)