sqrchain

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Diagnostics;

namespace sqr
{
    class Program
    {
        static void Main(string[] args)
        {
            Stopwatch sw = new Stopwatch();
            sw.Start();
            int res = 0;
            int x = 10000000;
            while (x!=0)
            {
                if (sqrchan89(x)) res++;
                x--;
            }
            Console.WriteLine(res);
            sw.Stop();
            Console.WriteLine(sw.Elapsed);
            Console.ReadLine();
        }
        public static int sqrSum(int number)
        {
            int res = 0;
            while (number > 0)
            {
                int x = number % 10;
                res += (int)Math.Pow(x,2);
                number /= 10;
            }

            return res;
        }
        static bool sqrchan89(int number)
        {
            if (number == 89) return true;
            else if (number == 1) return false;
            else return sqrchan89(sqrSum(number));
        }
    }
}