using System;

​

public class program

{

    public static void Main()

    {

        int i,n, sum = 0;

        Console.WriteLine("T");

        n =Convert.ToInt32(Console.ReadLine());

        for ( i = 1; i <= n ; i++)

        {

            Console.Write("{0}", i);

            sum += i;

    }

        Console.WriteLine("The sum of natural number {0}, sum : {1}", n,sum);

}

}