using System;

using System.Linq;

using System.Threading.Tasks;

using System.Collections.Generic;

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine((123456789f).ToString("#,##0"));

        Console.WriteLine((12345.6789f).ToString("#,##0"));

        Console.WriteLine((0f).ToString("#,##0"));

        Console.WriteLine((-1f).ToString("#,##0"));

        Console.WriteLine((123456789f).ToString("n0"));

    }

}