using System;

public class Program

{

    public static void rec(int n, int z, int sum, int y)

        {

            z++; sum = z;

            do

            {

                Console.Write(y);

                y++;

                z--;

            }

            while (z > 0);

            z = sum; y = 1;

            Console.WriteLine();

            if (n == 1)

            {

                return;

            }

            rec(n - 1, z, sum, y);

            do

            {

                Console.Write(y);

                y++;

                z--;

            }

            while (z > 0);

            Console.WriteLine();

        }

        public static void Main(string[] args)

        {

            Console.Write("Natural number: "); int n = int.Parse(Console.ReadLine());

            Console.WriteLine("===================");

            if (n < 1) Console.WriteLine("The number you have written is not a natural number!");

            else

            {

                int z = 0; int sum = 1; int y = 1;

                rec(n, z, sum, y);

            }

            Console.WriteLine("===================");

        }

}