using System;
using System.Linq;
using System.Text.RegularExpressions;

public class Test
{
	public static void Main()
	{
		var s = "This- -is - a test-sentence. -Test- --- One-Two--Three---Four----.";
    		var result = Regex.Replace(s, @"\b(-+)\b|-", "$1");
       		Console.WriteLine(result);
	}
}