from lib import *
import hashlib

part_1 = True

if part_1:
    digits = 5
else:
    digits = 6

data = open(0).read().strip()

for i in range(10**9):
    text = data + str(i)
    md5_hash = hashlib.md5(text.encode()).hexdigest()
    for c in md5_hash[:digits]:
        if c != "0":
            break
    else:
        print(i)
        break