Stacks and Queues - 09. Simple Text Editor

using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Advanced
{
    class Program
    {
        static void Main(string[] args)
        {
            int number = int.Parse(Console.ReadLine());
            string text = string.Empty;
            var stackText = new Stack<string>();

            for (int i = 0; i < number; i++)
            {
                string[] line = Console.ReadLine().Split();

                string command = line[0];

                switch (command)
                {
                    case "1":
                        string textToAdd = line[1];
                        stackText.Push(text);
                        text += textToAdd;
                        break;

                    case "2":
                        int count = int.Parse(line[1]);

                        if (count > text.Length)
                        {
                            count = Math.Min(count, text.Length);
                        }

                        stackText.Push(text);
                        text = text.Substring(0, text.Length - count);
                        break;

                    case "3":
                        int index = int.Parse(line[1]);
                        Console.WriteLine(text[index - 1]);
                        break;

                    case "4":
                        text = stackText.Pop();
                        break;
                }
            }
        }
    }
}