inpt = input()

def rec(s: str) -> int:
    if len(s) == 0:
        return 0

    while (s[0] == "0"):
        if (s == "0"):
            return 0
        s = s[1:]

    results = []
    for i in range(0,len(s)):
        results.append( rec(s[:i] + s[i+1:]))
    return max(results) + (1 if isPrime(int(s)) else 0)

def isPrime(a: int):
    if (a == 1 or a == 0):
        return False
    if (a == 2):
        return True
    if (a % 2 == 0):
        return False
    for i in range(3, int(a ** 0.5), 2):
        if (a % i == 0):
            return False

    return True
r = rec(inpt)

print(r)