using System;

using System.Globalization;

public class Program

{

    public static void Main()

    {

        string arfat ="1233445788.1212"; 

        decimal d = decimal.Parse(arfat);

        var a=(d.ToString("N"));

        Console.WriteLine(d.ToString("N4", CultureInfo.InvariantCulture));

        decimal b =decimal.Parse(a);

        Console.WriteLine(a);

    }

}