inp = input()

def isPrime(x):
    x = int(x)
    if x <= 1: return False
    if (x % 2 == 0 and x!= 2) or (x % 3 == 0 and x != 3) or (x % 5 == 0 and x != 5) or (x % 7 == 0 and x != 7): return False
    return True

def solve(x, res=0):
    if isPrime(int(x)):
        print(x, "is prime, adding")
        res += 1
    else: return res
    if len(x) == 1: return res

    currRes = res + 1
    currRes -= 1
    for i in range(len(x)):
        c = str(int(x))
        c = c[0:i]+c[i+1:] # del c[i]
        print("Conv", c)
        c = str(int(c))
        res = max(res, solve(c, currRes))
    
    return res
# print(isPrime(773))
print(solve(inp))