using System;

using System.Xml.Serialization;

using System.IO;

using System.Data;

using System.Linq;

using System.Data.DataSetExtensions;

public class Program

{

    public static void Main()

    {

        string test = Program.CheckSum("1Z89R93R680003004").ToString(); 

        Console.WriteLine(test);

    }

    public static char CheckSum(string waybill)

    {

        if (!waybill.Length.Equals(17)) return new char();

        waybill = waybill.Substring(2, waybill.Length -2);

        int odd = 0;

        int even = 0;

        int cx = 1;

        int sz = (waybill.Trim().Length);

        while(cx < sz)

        {

            char chold = char.Parse(waybill.Substring(cx, 1).ToUpper());

         if(((int)chold) < 91 & (int)chold > 64)

         {

             char chnew = ((char)((int)chold -3).ToString()[1]);

             waybill = (waybill.Substring(0, cx) + chnew + waybill.Substring(cx + 1, sz -(cx + 1)));

         }

         cx++;

        }

        cx = 1;

        while(cx < sz)

        {

            if(!(cx % 2).Equals(1))

            {

                odd = odd + Convert.ToInt16(waybill[cx].ToString());

            } else 

            {

                even = even + Convert.ToInt16(waybill[cx].ToString());

            }

            cx++;

        }

        even = even * 2;

        int retINT = 10 - (odd + even) % 10;

        if(retINT.Equals(10)) 

            retINT = 0;

        var s = (char)(retINT + 48);

        return s;

    }

}