from math import log10

def isPrime(num):
    if (num == 0 or num == 1): return False
    if (num == 2): return True
    if (num % 2 == 0): return False
    i = 3
    while (i*i < num+1):
        if (num % i == 0): return False
        i+=2
    return True

# print(isPrime(300107))

num = int(input())
# rez = 0
rez = int(isPrime(num))
while (num > 9):
    numS = str(num)
    # print("fitst: " + numS)
    numS = numS[1:]
    num = int(numS)
    # print(numS)

    # numLen = int(log10(num))+1
    # print(f"NumLen: {numLen}")
    # last = num // pow(10, numLen-1)
    # num = num - (last*pow(10, numLen-1))
    # print(f"New num: {num}, len: {numLen}, last: {last}")
    rez += int(isPrime(num))
print(rez)