using static System.Console;

using static System.Convert;

public class Program {

    public static void Main() {

        WriteLine(GenerateKey("10000"));

        WriteLine(GenerateKey("10011"));

        WriteLine(GenerateKey("10100"));

        WriteLine(GenerateKey("00000"));

        WriteLine(GenerateKey("999999999"));

    }

    public static int GenerateKey(string s) {           

        s = s.Remove(s.Length - 1);

        var i = ToInt32(s);

        var sum = 0;

        while (i != 0) {

            sum += i % 10;

            i /= 10;

        }

        var somatorio = ToInt32(s) + 1;

        var id = somatorio.ToString();

        if (sum.ToString().Length > 1) sum %= 10;

        id += sum;

        return ToInt32(id);

    }

}