using System;

using System.Collections.Generic;

using System.Text.RegularExpressions;

public class Program

{

    public static bool checkXml(String input)

    {

        Stack<string> startStack = new Stack<string>();

        Regex regx = new Regex("<[^<>]+>");

​

        foreach (Match match in regx.Matches(input))

        {

            if(match.Value.StartsWith("</"))

            {

                if(startStack.Count>0 && startStack.Peek().Equals(match.Value.Replace("</","<")))

                {   

                    startStack.Pop();

                    Console.WriteLine("stack pop: "+String.Join(" ", startStack));

                }

​

            }

            else

            {

                startStack.Push(match.Value);

                Console.WriteLine("stack push "+String.Join(" ", startStack));

            }

        }

​

        return startStack.Count==0;

    }

​

    public static void Main()

    {

        //Test Case1

        string input1 = "<Design><Code>Hello World</Code></Design>";

        Console.WriteLine("input: "+input1);

        Console.WriteLine(checkXml(input1));

        //Test Case2

        string input2 = "<Design><Code>Hello World</Code></Design><People>";

        Console.WriteLine("input: "+input2);

        Console.WriteLine(checkXml(input2));

        //Test Case3

        string input3 = "<People><Design><Code>Hello World</People></Code></Design>";

        Console.WriteLine("input: "+input3);

        Console.WriteLine(checkXml(input3));

        //Test Case4

        string input4 = "<a><b>bvalue</b><c>cvalue</c><d><e>evalue</e><f>fvalue</f></d></a>";

        Console.WriteLine("input "+input4);

        Console.WriteLine(checkXml(input4));

    }

}