def isPrime(num):
    if (num == 0 or num == 1): return False
    if (num == 2 or num == 3): return True
    if (num % 2 == 0): return False
    i = 3
    while (i*i <= num+3):
        if (num % i == 0): return False
        i+=2
    return True
# primes = (i for i in range(100))
# for prime in primes:
#     print(f"{prime} -> {isPrime(prime)}")

num = int(input())
rez = int(isPrime(num))
if (rez):
    while (num > 9):
        numS = str(num)
        numS = numS[1:]
        num = int(numS)
        if (isPrime(num)):
            rez += 1
        else: break
print(rez)