using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine(ConcatBidirectional());

        Console.WriteLine(Environment.NewLine);

        Console.WriteLine(ConcatBidirectionalWithFormat());

        Console.WriteLine(Environment.NewLine);

        Console.WriteLine(ConcatBidirectionalWithJoin());

    }

    public static string ConcatBidirectional()

    {

        string IdWithSubType = "طائرات هليكوبت";

        string MiddleString = "(100252575";

        string EndString = "@vk.com";

        string ltr = ((char)0x200E).ToString();

        return string.Format("{0}{1}{2}", IdWithSubType, MiddleString, EndString);

    }

    public static string ConcatBidirectionalWithFormat()

    {

        string IdWithSubType = "طائرات هليكوبت";

        string MiddleString = "(100252575";

        string EndString = "@vk.com";

        string ltr = ((char)0x200E).ToString();

        return string.Format("{0}{1}{2}{3}", IdWithSubType, ltr, MiddleString, EndString);

    }

    public static string ConcatBidirectionalWithJoin()

    {

        string IdWithSubType = "طائرات هليكوبت";

        string MiddleString = "(100252575";

        string EndString = "@vk.com";

        string ltr = ((char)0x200E).ToString();

        return string.Join(ltr, IdWithSubType, MiddleString, EndString);

    }

}