02.Detective Boev

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

class DetectiveBoev
{
    static void Main()
    {
        string secretWord = Console.ReadLine();
        string message = Console.ReadLine();

        int sum = 0;
        for (int i = 0; i < secretWord.Length; i++)
        {
            sum += (int)secretWord[i];
        }

        while (sum /10 != 0)
        {
            int newSum = 0;
            while (sum > 0)
            {
                newSum += sum % 10;
                sum /= 10;
            }
            sum = newSum;
        }
        StringBuilder str = new StringBuilder(message);
        for (int i = 0; i < str.Length; i++)
        {
            if (str[i] % sum == 0)
            {
                str[i] = (char)((int)str[i] + sum);
            }
            else
            {
                str[i] = (char)((int)str[i] - sum);
            }
        }
        message = str.ToString();
        char[] arr = message.ToCharArray();
        Array.Reverse(arr);
        Console.WriteLine(new string(arr));
    }
}