On Time For Exam

            int examHour = int.Parse(Console.ReadLine());
            int examMin = int.Parse(Console.ReadLine());
            int arrivalHour = int.Parse(Console.ReadLine());
            int arrivalMin = int.Parse(Console.ReadLine());

            TimeSpan examTS = new TimeSpan(examHour, examMin, 0);
            TimeSpan arrivalTS = new TimeSpan(arrivalHour, arrivalMin, 0);

            TimeSpan zero = new TimeSpan(0, 0, 0);
            TimeSpan min30 = new TimeSpan(0, 30, 0);
            TimeSpan min60 = new TimeSpan(1, 0, 0);

            TimeSpan interval = arrivalTS - examTS;

            if (interval > zero)
            {
                Console.WriteLine("Late");
                if (interval >= min60)
                {
                    Console.WriteLine($"{interval.ToString(@"h\:mm")} hours after the start");
                }
                else
                {
                    Console.WriteLine($"{interval.ToString("mm")} minutes after the start");
                }
            }
            else
            {
                if (interval == zero)
                {
                    Console.WriteLine("On time");
                }
                else if (interval >= -min30)
                {
                    Console.WriteLine("On time");
                    Console.WriteLine($"{interval.ToString("mm")} minutes before the start");
                }
                else if (interval > -min60)
                {
                    Console.WriteLine("Early");
                    Console.WriteLine($"{interval.ToString("mm")} minutes before the start");
                }
                else
                {
                    Console.WriteLine("Early");
                    Console.WriteLine($"{interval.ToString(@"h\:mm")} hours before the start");
                }

            }