class DateSerial
        {
            public DateTime Date;
            public int Serial;

            public DateSerial(DateTime date)
            {
                Date = date;
                Serial = 0;
            }

            public override string ToString()
            {
                return string.Format("{0} {1}", Date.ToString("yyyy-MM-hh"), Serial);
            }
        }

        static void Sort(List<DateSerial> dateList)
        {
            DateTime minDate = new DateTime(0);

            for (int i = 0; i < dateList.Count; i++)
            {
                DateTime tempDate = DateTime.Parse("2099-1-1");

                for (int j = 0; j < dateList.Count; j++)
                {
                    if (dateList[j].Date > minDate)
                    {
                        dateList[j].Serial++;
                        tempDate = dateList[j].Date < tempDate ? dateList[j].Date : tempDate;
                    }
                }

                minDate = tempDate;
            }
        }

        static void Main(string[] args)
        {
            List<DateSerial> dateList = new List<DateSerial>();

            dateList.Add(new DateSerial(DateTime.Parse("2009-03-01")));
            dateList.Add(new DateSerial(DateTime.Parse("2008-06-12")));
            dateList.Add(new DateSerial(DateTime.Parse("2009-01-12")));
            dateList.Add(new DateSerial(DateTime.Parse("2008-06-12")));
            dateList.Add(new DateSerial(DateTime.Parse("2007-06-14")));
            dateList.Add(new DateSerial(DateTime.Parse("2008-09-18")));
            dateList.Add(new DateSerial(DateTime.Parse("2004-01-12")));

            Sort(dateList);

            foreach (DateSerial d in dateList)
            {
                Console.WriteLine(d);
            }

            Console.ReadLine();
        }