using System;

using System.Linq;

using System.Collections.Generic;

using System.Text.RegularExpressions;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

        string input = "Products > Social  Studies > History > US";

        input = Regex.Replace(input, @"\s+", " ");

        List<string> myList = input.Split(">")

            .Select(tag => tag.Trim())

            .Where( tag => !string.IsNullOrEmpty(tag)).ToList();

        myList = myList.ConvertAll(d => d.ToLower().Replace(" ", "_"));

        foreach(var crumb in myList){

            Console.WriteLine("'" + crumb + "'");

        }

        string asString = String.Join("|", myList);

        Console.WriteLine("\n'" + asString + "'");

    }

}