using System;

using System.Linq;

using System.Text;

​

public class Program

{

    public static void Main()

    {

        var input = "104, 101, 108, 108, 111, 44, 32, 119, 111, 114, 108, 100";

        var data = Array.ConvertAll( 

            input.Split(',').Select( e => e.Trim() ).ToArray(),

            Byte.Parse );

        var str = Encoding.ASCII.GetString(data);

        Console.WriteLine(str);

    }

}