import sys
import math

def all_same(s):
    return all(c == s[0] for c in s)

def main():
    s = sys.stdin.readline().strip()
    if all_same(s):
        print(s)
        return
    # Compute sum of digits
    total = sum(int(c) for c in s)
    # Compute GCD of non-zero digits
    g = 0
    for c in s:
        d = int(c)
        if d != 0:
            if g == 0:
                g = d
            else:
                g = math.gcd(g, d)
    # Compute P and G
    P = g * 9
    G = math.gcd(total, P)
    print(G)

if __name__ == "__main__":
    main()