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

namespace CeaserCode
{
    class Program
    {
        static void Main(string[] args)
        {
#region code
            StreamReader st = new StreamReader("input.txt");
            StreamWriter ou = new StreamWriter("output.txt");
            StreamWriter fou = new StreamWriter("finaloutput.txt");
            //StreamReader st1 = new StreamReader("output.txt");

            string input = null;
            string local = null;
            string output = null;
            Console.WriteLine("vvedite sdvig");
            int sdvig = Convert.ToInt32(Console.ReadLine());
            //char a = 't';
            //char b = 'z';
            //Console.WriteLine(Convert.ToInt32(a));
            //Console.WriteLine(Convert.ToInt32(b));

            while (true)
            {
                local = st.ReadLine();
                if (local == null) break;
                input += local;
                //local.ToUpper();
            }
            //Console.WriteLine(input);
            Char[] LettersUnconverted = new Char[input.Length];
            input = input.ToLower();
            LettersUnconverted = input.ToCharArray();
            for (int i = 0; i < LettersUnconverted.Length; i++)
            {
                if (Char.IsLetter(LettersUnconverted[i]))
                {

                    int j = Convert.ToInt32(LettersUnconverted[i]) - 97;
                    j += sdvig;
                    j = j % 26;
                    j += 97;
                    output = output + Convert.ToChar(j);
                }
                else output = output + LettersUnconverted[i];

            }
            ou.WriteLine(output);
            //Console.WriteLine(output);
            Console.ReadLine();
            #endregion
            #region decode
            //while (true)
            //{
            //    local = st1.ReadLine();
            //    if (local == null) break;
            //    input += local;
            //    //local.ToUpper();
            //}
            string decodeinp = output;
            char[] alphabet = new char[26] { 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z' };
            double[] friqency = new double[26] { 8.16, 1.49, 2.78, 4.25, 12.7, 2.28, 2.01, 6.09, 6.96, 0.15, 0.77, 4.02, 2.4, 6.75, 7.5, 1.92, 0.09, 5.98, 6.32, 9.05, 2.75, 0.97, 2.36, 0.15, 1.97, 0.07 };
            int totalcount = 0;
            int[] count = new int[26];
            Double[] Count = new Double[26];
            char[] decodelet = new char[decodeinp.Length];
            decodelet = decodeinp.ToCharArray();
            for (int i = 0; i < decodelet.Length; i++)
            {
                if (char.IsLetter(decodelet[i]))
                {
                    int j = Convert.ToInt32(decodelet[i]) - 97;
                    count[j]++;
                    totalcount++;
                }

            }

            int control = 0;

            for (int i = 0; i < 26; i++)
            {
                Count[i] = (Convert.ToDouble(count[i]) / totalcount) * 100;

            }



            for (int i = 0; i < 26; i++)
                if (Count[i] == Count.Max())
                    control = i;
            int popravka = 4 - control;
            string finaloutput = null;
            for (int i = 0; i < decodeinp.Length; i++)
            {
                if (Char.IsLetter(decodeinp[i]))
                {
                    int j = Convert.ToInt32(decodeinp[i]) - 97;
                    j = j + popravka;
                    if (j < 0)
                    {
                        j = j + 26;
                    }
                    //j = j % 26;
                    j += 97;
                    finaloutput = finaloutput + Convert.ToChar(j);
                    j = 0;
                }
                else finaloutput = finaloutput + decodeinp[i];

            }
            fou.WriteLine(finaloutput);

            //Console.ReadLine();
            #endregion
            Console.WriteLine("Закодированный файл находится в файле 'output'. Декодированный файл находится в файле 'finaloutput'.");
            Console.ReadLine();
        }
    }
}