using System;

using System.Text.RegularExpressions;

public class Program

{

    public static void Main()

    {

        //

        // String containing numbers.

        //

        string sentence = "---hello--- hello ------- hello --- bye";

        //

        // Get all digit sequence as strings.

        //

        string[] result = Regex.Split(sentence, @"(?<!-)---(?!-)");

        //

        // Now we have each number string.

        //

        foreach (string value in result)

        {

         Console.WriteLine(value.Trim());

        }

    }

}