def is_prime(num): if num < 2: return False for i in range(2, int(num ** 0.5) + 1): if num % i == 0: return False return True def is_super_prime(num): if not is_prime(num): return False while num > 0: if not is_prime(num): return False num //= 10 return True def super_primes(n): result = [] for i in range(2, n+1): if is_super_prime(i): result.append(i) return result n = int(input()) print(len(super_primes(n)))