Warriors Quest

using System;
using System.Text;

namespace _01._Warrior_s_Quest
{
    class Program
    {
        static void Main(string[] args)
        {
            string skill = Console.ReadLine();

            string input = Console.ReadLine();
            while (input != "For Azeroth")
            {
                string[] tokens = input.Split(" ");
                string command = tokens[0];

                if (command == "GladiatorStance")
                {
                    skill = skill.ToUpper();
                    Console.WriteLine(skill);
                }
                else if (command == "DefensiveStance")
                {
                    skill = skill.ToLower();
                    Console.WriteLine(skill);
                }
                else if (command == "Dispel")
                {
                    var indexToReplace = int.Parse(tokens[1]);
                    char charToReplace = char.Parse(tokens[2]);

                    if (indexToReplace < skill.Length && indexToReplace >= 0)
                    {
                        char[] temp = skill.ToCharArray();
                        temp[indexToReplace] = charToReplace;

                        skill = new string(temp);
                        Console.WriteLine("Success!");
                    }
                    else
                    {
                        Console.WriteLine("Dispel too weak.");
                    }
                }
                else if (command == "Target")
                {
                    var action = tokens[1];
                    if (action == "Change")
                    {
                        var substring = tokens[2];
                        var newString = tokens[3];
                        if (skill.Contains(substring))
                        {
                            skill = skill.Replace(substring, newString);
                            Console.WriteLine(skill);
                        }
                    }
                    else if (action == "Remove")
                    {
                        var substring = tokens[2];
                        if (skill.Contains(substring))
                        {
                            var index = skill.IndexOf(substring);

                            skill = skill.Remove(index, substring.Length);
                            Console.WriteLine(skill);
                        }
                        else
                        {
                            Console.WriteLine("Command doesn't exist!");
                        }
                    }
                }

                else
                {
                    Console.WriteLine("Command doesn't exist!");
                }

                input = Console.ReadLine();
            }

        }
        }
    }