using System;
using System.Text.RegularExpressions;

public class Test
{
	public static void Main()
	{
		Console.WriteLine(Regex.Escape("-"));
		String product = "BK III";
		String[] titles = { "product BKIII", "product BK III", "product BK-III", "product BKII" };
		String escapedModelNumber = Regex.Escape(product.ToLower());
		String variableModelNumber = Regex.Replace(escapedModelNumber, @"\\ |-", "[ -]*");
		String pattern = $@"\b{variableModelNumber}\b";
		foreach (String s in titles) {
			Console.WriteLine(Regex.Replace(s, pattern, product, RegexOptions.IgnoreCase));
		}
	}
}