using System;

public class Program

{

    public static void Main()

    {

        double value = 12345.6789;

        Console.WriteLine(value.ToString("C3", System.Globalization.CultureInfo.CreateSpecificCulture("en-AU")));

        Console.WriteLine(value.ToString("C3", System.Globalization.CultureInfo.CreateSpecificCulture("en-DE")));

        Console.WriteLine(value.ToString("C3", System.Globalization.CultureInfo.CreateSpecificCulture("de-DE")));

    }

}