static void Main(string[] args)
        {
            long i = 7;
            i = Convert.ToInt64(Console.ReadLine());
            Stopwatch s = new Stopwatch();
            s.Start();
            const double gr = 1.6180339887;
            const double s5 = 2.2360679774997896;
            i = Convert.ToInt64((Math.Pow(gr, i) - Math.Pow(1 - gr, i)) / s5);
            s.Stop();
            Console.WriteLine("F: {0}\nT: {1}", i, s.Elapsed.Milliseconds);
            Console.ReadLine();
            return;
        }