import math


def is_prime(n):
    if n < 2:
        return False
    if n == 2:
        return True
    if n % 2 == 0:
        return False

    sqrt_n = int(math.floor(math.sqrt(n)))
    for i in range(3, sqrt_n + 1, 2):
        if n % i == 0:
            return False
    return True


def recursion(cislo):
    vysledky = []
    while cislo[0] == '0': cislo = cislo[1:]
    for i in range (len(cislo)):
        newcislo = cislo[:i] + cislo[i+1:]
        if newcislo == "":
            return 0
        if is_prime(int(newcislo)):
            vysledky.append(recursion(newcislo) + 1)
        else:
            vysledky.append(0)
    return max(vysledky)


if __name__ == '__main__':
    zk = int(input())
    zk = str(zk)
    print(recursion(zk)+int(is_prime(int(zk))))