N = int(input())

def is_prime(N):
    if (N == 0 or N == 1):
        return 0
    for i in range(2, N):
        if N % i == 0:
            return 0
    return 1

k = is_prime(N)
if k == 0:
    print(0)
else:
    st = list(str(N))
    while int("".join(st)):
        st[0] = '0'
        if is_prime(int("".join(st))):
            k += 1
        else:
            break
        st = list(str(int("".join(st))))

    print(k)