using System;

using System.Text;

public class Program

{

    public static void Main()

    {

            var listString = "1,2,50-60,99";

            var newList = new StringBuilder();

            var arr = listString.Split(',');

            foreach (var s in arr)

            {

                if(s.Contains("-"))

                {

                    var pair = s.Split('-');

                    int xfrom = 0, xto = 0;

                    if(Int32.TryParse(pair[0], out xfrom) && Int32.TryParse(pair[1], out xto) )

                    {

                        if(xto-xfrom>1000)

                        {

                            throw new Exception("Segment greater than 1000: " + s );

                        }

                        for (int i = xfrom; i <= xto; i++)

                        {

                            newList.AppendFormat("{0},", i);

                        }

                    }

                }

                else

                {

                    newList.AppendFormat("{0},",s.Trim());

                }

            }           

        Console.WriteLine("Result: {0}", newList);

    }

}