using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("please enter a natural number!");

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

        int y=0;

      while(n>0) 

      { 

          y=y*10+n%10;

          n/=10;

      }

          Console.WriteLine("{0}",y);

    }

}