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

namespace Task_1._3
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Input number a: ");
            string a = Console.ReadLine();
            int w = 0;
            int z = 10;
            int[] b = new int[a.Length];
            for (int i = 0; i < a.Length; i++)
            {
                b[i] = Convert.ToInt32(a.Substring(i, 1));
                w = w + b[i] * z;
                z--;
            }
            int x;
            if (w % 11 != 0)
            {
                x = (w / 11 + 1) * 11 - w;

            }
            else
            {
                x = 0;
            }
            if (x == 10)
            { Console.WriteLine(a + 'X'); }
            else
            {
                Console.WriteLine(a + x);
            }
            Console.ReadLine();
        }
        }
    }