using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

​

namespace TD1

{

    public class Program

    {

        public static void Main(string[] arg)

        {   

            for (int i = 20 ; i<=40; i++)

            {

                Console.Write(i + " ");

                i++;

            }   

        }

    }

}