using System;

public class Program

{

    public static int Bikoret(string tz)

    {

        int i, sum = 0, temp;

        for(i = 0; i < tz.Length; i++)

        {

            if(i % 2 == 0)

            {

                sum += (tz[i] - 48);

            }

            else

            {

                temp = ((tz[i] - 48) * 2);

                if(temp > 9)

                {

                    temp = temp % 10 + temp / 10;

                    sum += temp;

                }

                else

                    sum += temp;

            }

        }

        if(sum % 10 == 0)

            return 0;

        else

            return 10-(sum%10);

    }

    public static bool tz_checker(string tz)

    {

        int i, sum = 0, temp;

        for(i = 0; i < tz.Length; i++)

        {

            if(i % 2 == 0)

            {

                sum += (tz[i] - 48);

            }

            else

            {

                temp = ((tz[i] - 48) * 2);

                if(temp > 9)

                {

                    temp = temp % 10 + temp / 10;

                    sum += temp;

                }

                else

                    sum += temp;

            }

        }

        if(sum % 10 == 0)

        {

            if((tz[tz.Length-1] - 48) == 0)

                return true;

        }

        if((tz[tz.Length-1] - 48) == (10 - (sum % 10)))

        {

            return true;

        }

        return false;

    }

    public static void Main()

    {

        string tz;

        Console.WriteLine("Enter your tz without bikoret num: ");

        tz = Console.ReadLine();

        Console.WriteLine("Your bikoret num is: " + Bikoret(tz));

        Console.WriteLine("Enter your tz with bikoret num: ");

        tz = Console.ReadLine();

        Console.WriteLine("Your tz is: " + tz_checker(tz));

    }

}