import math

def compute_gcd(n_str):
    # Check if all characters are the same
    if all(c == n_str[0] for c in n_str):
        return n_str
    
    # Compute sum of digits
    s = sum(int(c) for c in n_str)
    
    # Compute minimal element m
    digits = sorted(n_str)
    # Find the first non-zero digit
    first_non_zero = next(i for i, d in enumerate(digits) if d != '0')
    # Form the minimal element
    minimal_digits = [digits[first_non_zero]] + digits[:first_non_zero] + digits[first_non_zero+1:]
    m_str = ''.join(minimal_digits)
    
    # Compute m mod s
    mod = 0
    for c in m_str:
        mod = (mod * 10 + int(c)) % s
    
    # GCD of s and mod
    g = math.gcd(s, mod)
    return str(g)

n = input().strip()
print(compute_gcd(n))