Sudoku_Result

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

namespace _02.Sudoku_Result
{
    class Sudoku_Result
    {
        static void Main(string[] args)
        {
            string  format;
            TimeSpan timeInterval = new TimeSpan(0,0,0);
            TimeSpan timeSum      = new TimeSpan(0, 0, 0);

            CultureInfo culture;
            culture = CultureInfo.InvariantCulture;
            format = "mm\\:ss";
            string command = "";
            int counter = 1;

            while (command != "Quit")
            {
                timeInterval = TimeSpan.ParseExact(Console.ReadLine(), format, culture);
                command = Console.ReadLine();
                timeSum += timeInterval;
                counter++;
            }
            bool isGold = (timeSum.TotalSeconds) / counter < 720;

            if (isGold)
            {
                Console.WriteLine("Gold Star");
                Console.WriteLine("Games - {0} \\ Average seconds - {1}",counter, Math.Floor(timeSum.TotalSeconds/ counter));
            }

            else if (timeSum.TotalSeconds / counter > 720 && timeSum.TotalSeconds / counter < 1440)
            {
                Console.WriteLine("Silver Star");
                Console.WriteLine("Games - {0} \\ Average seconds - {1}", counter, Math.Floor(timeSum.TotalSeconds / counter));
            }
            else
            {
                Console.WriteLine("Bronze Star");
                Console.WriteLine("Games - {0} \\ Average seconds - {1}", counter, Math.Floor(timeInterval.TotalSeconds / counter));
            }
        }
    }
}