modulo 11 remainder

def mod_eleven(num_str):
    odd_sum = 0
    even_sum = 0
    
    for i, digit in enumerate(reversed(num_str)):
        if i % 2 == 0:
            odd_sum += int(digit)
        else:
            even_sum += int(digit)
    
    return (odd_sum - even_sum) % 11

num_str = input().strip()
print(mod_eleven(num_str))