SpyGram

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading.Tasks;

namespace _02_SpyGram
{
    class Program
    {
        static void Main(string[] args)
        {
            var pattern = @"^TO: ([A-Z]+); MESSAGE: (.+);$";
            var validatoin = new Regex(pattern);
            var pendingMessages = new Dictionary<string, List<string>>();
            var key = Console.ReadLine();

            while (true)
            {
                var inputLine = Console.ReadLine();
                if (inputLine == "END")
                {
                    break;
                }
                var isMatch = validatoin.IsMatch(inputLine);
                if (!isMatch)
                {
                    continue;
                }

                var senderName = validatoin.Match(inputLine).Groups[1].ToString();


                var sb = new StringBuilder();
                var simbolOfKey = key.ToCharArray();

                var positionOfSimbols = 0;
                for (int i = 0; i < key.Length; i++)
                {
                    var result = (char)(inputLine[positionOfSimbols] + int.Parse(simbolOfKey[i].ToString()));
                    sb.Append(result);
                    if (i == key.Length - 1)
                    {
                        i = -1;
                    }
                    positionOfSimbols++;
                    if (positionOfSimbols == inputLine.Length)
                    {
                        break;
                    }
                }

                if (!pendingMessages.ContainsKey(senderName))
                {
                    pendingMessages[senderName] =new List<string>();
                }
                pendingMessages[senderName].Add(sb.ToString());
            }

            foreach (var item in pendingMessages.OrderBy(x => x.Key))
            {
                foreach (var message in item.Value)
                {
                    Console.WriteLine(message);
                }
            }
        }
    }
}