Detective Boev

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

namespace FourFactors
    {
    class DetectiveBoev
        {
        static void Main()
            {
            string secretWord = Console.ReadLine();
            string encrypMess = Console.ReadLine();
            int count = 0;
            foreach (char item in secretWord)
                {
                count += (int)item;
                }
            string countString = count.ToString();
            count = 0;
            while (countString.Length > 1)
                {
                foreach (var item in countString)
                    {
                    count += (int)char.GetNumericValue(item);
                    }
                countString = count.ToString();
                count = 0;
                }
            count = int.Parse(countString);
            string decrMess = null;
            foreach (var item in encrypMess)
                {
                if (item % count == 0)
                    {
                    decrMess += (char)(item + count);
                    }
                else
                    {
                    decrMess += (char)(item - count);
                    }
                }
            string decrMessRev = new string(decrMess.ToCharArray().Reverse().ToArray());
            Console.WriteLine(decrMessRev);
            }
        }
    }