#!/usr/bin/env python3
# -*- coding: utf-8 -*-

# MIT License
#
# Copyright (c) 2016 Israel Bermudez
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.

import sys
import getopt
from math import ceil

STD_MULTS = [1, 3, 1, 3, 1, 3, 1, 3, 1, 3, 1, 3, 1, 3, 1, 3]

in_bol = input("BOL Number: ")

if len(in_bol) != 16:
    print("BOL number must have 16 Characters!\n")
else:
    BOL = list(map(int, in_bol))

    print(BOL)
    print(str(len(BOL)))

    mul = list()
    n_sum = 0

    for i in range(16):
        mul.append(BOL[i] * STD_MULTS[i])
        n_sum += mul[i]

    check_digit = ((ceil(n_sum / 10.0)*10) - n_sum)

    print(check_digit)