OnTimeForTheExam

using System;

namespace OnTimeForExam
{
    class Program
    {
        static void Main(string[] args)
        {
            int examHour = int.Parse(Console.ReadLine());
            int examMin= int.Parse(Console.ReadLine());
            int arrivalHour = int.Parse(Console.ReadLine());
            int arrivalMin = int.Parse(Console.ReadLine());

            int diffMin = Math.Abs(examMin - arrivalMin);
            int diffHour = Math.Abs(examHour - arrivalHour);

            //(1)
            if (arrivalHour == examHour)
            {
                if (arrivalMin<=examMin && arrivalMin >= (examMin - 30))
                {
                    Console.WriteLine("On time");
                }
                else if (arrivalMin > examMin)
                {
                    Console.WriteLine("Late");
                    Console.WriteLine($"{diffMin} minutes after the start");
                }
                else if (arrivalMin<examMin)
                {
                    Console.WriteLine("Early");
                    Console.WriteLine($"{diffMin} minutes before the start");
                }
            }
            //(2)
            else if (arrivalHour>examHour)
            {
                if (arrivalHour == (examHour + 1) && arrivalMin<examMin)
                {
                    Console.WriteLine("Late");
                    Console.WriteLine($"{arrivalMin+60-examMin} minutes after the start");
                }
                else
                {
                    Console.WriteLine("Late");
                    Console.WriteLine($"{diffHour}:{diffMin:D2} hours after the start");
                }
            }
            //(3)
            else if (arrivalHour < examHour)
            {
                if (arrivalHour == (examHour - 1) && (60 + examMin - arrivalMin) <= 30)
                {
                    Console.WriteLine("On time");
                    Console.WriteLine($"{60 + examMin - arrivalMin} minutes before the start");
                }
                else if (arrivalHour == (examHour - 1) && (60 + examMin - arrivalMin) > 30 && (60 + examMin - arrivalMin)<=59)
                {
                    Console.WriteLine("Early");
                    Console.WriteLine($"{60 + examMin - arrivalMin} minutes before the start");
                }
                else if (arrivalHour < examHour && arrivalMin <= examMin)
                {
                    Console.WriteLine("Early");
                    Console.WriteLine($"{diffHour}:{diffMin:D2} hours before the start");
                }
                else if (arrivalHour<examHour && arrivalMin >examMin)
                {
                    Console.WriteLine("Early");
                    Console.WriteLine($"{diffHour-1}:{(60+examMin-arrivalMin):D2} hours before the start");
                }
            }
        }
    }
}