#gcd of permutation
from math import gcd


def main():
    s = input()
    M = int(s)
    a = list(map(int, list(s)))
    a.sort()
    N = len(a)
    if a[0] == a[-1]:
        print(int(s))
        return
    else:
        ans = 0
        G = 9*(a[-1] - a[0])
        for i in range(1, G+1):
            if G % i == 0:
                if M % i == 0:
                    ans = i
        print(ans)
        return


if __name__ == "__main__":
    main()