using System;

using System.Collections.Generic;

using System.Linq;

​

class Program

{

    private static IEnumerable<char> All() {

        for (var i = 0; i < 0xffff; i++) {

            yield return (char)i;

        }

    }

​

    static void Main(string[] args)

    {

        Console.WriteLine(string.Join(',', All().Where(char.IsNumber)));

    }

}

​