using System;

public class Program

{

    public static void Main()

    {

         int num = 20;

         Console.WriteLine(new Program().Solution(num));

    }

    public int Solution(int a)

        {

            if (a < 10)

            {

                return a;

            }

            else

            {

                int x = a / 9;

                int y = a % 9;

                double z =  Math.Pow(10,x) - 1;

                z = z + (y * Math.Pow(10, x));

                return (int)z;

            }            

        }

}