nikulden charity

using System;
using System.Linq;
using System.Collections.Generic;
using System.Text.RegularExpressions;
using System.Runtime.InteropServices;
using System.Data;
using System.IO;
using System.Reflection.PortableExecutable;

namespace _02._Boss_Rush
{
    class Program
    {
        static void Main(string[] args)
        {
            string input = Console.ReadLine();

            string[] command = Console.ReadLine().Split();

            while (command[0] != "Finish")
            {
                if (command[0] == "Replace")
                {
                    if (input.Contains(command[1]))
                    {
                        input = input.Replace(command[1], command[2]);
                    }
                }
                if (command[0] == "Cut")
                {
                    int index = int.Parse(command[1]);
                    int end = int.Parse(command[2]);
                    if ((index >= 0 && index < input.Length) && end >= 0 && end < input.Length)
                    {
                        int lenght = end - index + 1;
                        input = input.Remove(index, lenght);
                    }
                    else
                    {
                        Console.WriteLine("Invalid indexes!");
                        command = Console.ReadLine().Split();
                        continue;
                    }

                }
                if (command[0] == "Make")
                {
                    if (command[1] == "Upper")
                    {
                        input = input.ToUpper();
                    }
                    else
                    {
                        input = input.ToLower();
                    }
                }
                if (command[0] == "Check")
                {
                    if (input.Contains(command[1]))
                    {
                        Console.WriteLine($"Message contains {command[1]}");
                        command = Console.ReadLine().Split();
                        continue;
                    }
                    else
                    {
                        Console.WriteLine($"Message doesn't contain {command[1]}");
                        command = Console.ReadLine().Split();
                        continue;
                    }
                }
                if (command[0] == "Sum")
                {
                    int start = int.Parse(command[1]);
                    int end = int.Parse(command[2]);

                    if ((start >= 0 && start < input.Length) && end >= 0 && end < input.Length)
                    {
                        int lenght = end - start + 1;
                        string sub = input.Substring(start, lenght);
                        char[] subs = sub.ToCharArray();
                        int sum = 0;

                        foreach (var item in subs)
                        {
                            sum += item;
                        }
                        Console.WriteLine(sum);

                        command = Console.ReadLine().Split();
                        continue;
                    }
                    else
                    {
                        Console.WriteLine("Invalid indexes!");
                        command = Console.ReadLine().Split();
                        continue;
                    }
                }

                Console.WriteLine(input);
                command = Console.ReadLine().Split();
            }
        }
    }
}