using System;

using System.Globalization;

public class Program

{

    public static void Main()

    {

        double a = 12345.6789123467;

        string a1 = a.ToString("f5", CultureInfo.InvariantCulture);

        string a2 = a.ToString("N5", CultureInfo.InvariantCulture);

        Console.WriteLine(a1);

        Console.WriteLine(a2);

    }

}