var totalgroup= list.GroupBy(c => c.LeaveTime.Month).OrderBy(c=>c.Key);
            foreach (var item in totalgroup)
            {
                Console.WriteLine(item.Key+"月出院的人有：");
                foreach (var item2 in item)
                {
                    Console.WriteLine("病人："+item2.Name+"\t出院时间："+item2.LeaveTime);
                }
            }