import random
import time
start = time.time()
S = input()


def gcd(x, y):
    while(y):
        t = x
        x = y
        y = t % y
    return x


T = 0.93
g = int(S)
l = list(S)
s = int("".join(sorted(l)))
r = int("".join(reversed(l)))
g = gcd(g, gcd(s, r))

while time.time() < start + T:
    random.shuffle(l)
    g = gcd(g, int("".join(l)))

print(g)