String Game

using System;
using System.Text;

namespace Exam1_String
{
    class Program
    {
        static void Main(string[] args)
        {
            string input = Console.ReadLine();
            StringBuilder result = new StringBuilder(input);
            string command = Console.ReadLine();
            while (command != "Done")
            {
                string[] cmdSplitted = command.Split();
                if(cmdSplitted[0] == "Change")
                {
                    result.Replace(cmdSplitted[1], cmdSplitted[2]);
                    Console.WriteLine(result);
                }
                else if (cmdSplitted[0] == "Includes")
                {
                    string subString = cmdSplitted[1];
                    if (result.ToString().Contains(subString))
                        Console.WriteLine("True");
                    else
                        Console.WriteLine("False");

                }
                else if (cmdSplitted[0] == "End")//This is my string! == 17 length
                {

                    if (result.ToString().Contains(cmdSplitted[1]))//g! = 2 length
                    {

                        string subString = result.ToString().Substring(result.Length - cmdSplitted[1].Length);//17-2 = starts from 15
                        if (subString == cmdSplitted[1])// ako substringa e sushtiq kato ot inputa ..
                            Console.WriteLine("True");
                        else
                            Console.WriteLine("False");
                    }
                }
                else if (cmdSplitted[0] == "Uppercase")
                {
                    for (int i = 0; i < result.Length; i++)
                    {
                        result[i] = char.ToUpper(result[i]);
                    }
                    Console.WriteLine(result);
                }
                else if (cmdSplitted[0] == "FindIndex")
                {
                    int index = result.ToString().IndexOf(cmdSplitted[1]);
                    Console.WriteLine(index);
                }
                else if (cmdSplitted[0] == "Cut")
                {
                    int startIndex = int.Parse(cmdSplitted[1]);
                    int endIndex = int.Parse(cmdSplitted[2]);
                    string subString = result.ToString().Substring(startIndex, endIndex);
                    Console.WriteLine(subString);
                }


                command = Console.ReadLine();
            }


        }
    }
}