On time for exam

using System;

namespace OnTimeForExam
{
    class Program
    {
        static void Main(string[] args)
        {
            int hourExam = int.Parse(Console.ReadLine());
            int minuteExam = int.Parse(Console.ReadLine());
            int hourStudent = int.Parse(Console.ReadLine());
            int minuteStudent = int.Parse(Console.ReadLine());

            var firstCase = (hourExam * 60) + minuteExam;
            var secondCase = (hourStudent * 60) + minuteStudent;
            var change = firstCase - secondCase;
            var onTime = "On time";
            var early = "Early";
            var late = "Late";

            if (change>0)
            {
                if (change>=0&&change<=30)
                {
                    Console.WriteLine(onTime);
                    var hour = change / 60;
                    var minute = change % 60;
                    if (minute<=30)
                    {
                        Console.WriteLine($"{minute} minutes before the start");
                    }
                }
                else if (change > 30)
                {
                    Console.WriteLine(early);
                    var hour = change / 60;
                    var minute = change % 60;
                    if (hour<1)
                    {
                        Console.WriteLine($"{minute} minutes before the start");
                    }
                    else if (hour >= 1&&minute<10)
                    {
                        Console.WriteLine($"{hour}:0{minute} hours before the start");
                    }
                    else
                    {
                        Console.WriteLine($"{hour}:{minute} hours before the start");
                    }
                }
            }
            else if (change==0)
            {
                Console.WriteLine(onTime);
            }
            else
            {
                Console.WriteLine(late);
                var hour = change*-1 / 60;
                var minute = change*-1 % 60;
                if (hour < 1)
                {
                    Console.WriteLine($"{minute} minutes after the start");
                }
                else if (hour >= 1 && minute < 10)
                {
                    Console.WriteLine($"{hour}:0{minute} hours after the start");
                }
                else
                {
                    Console.WriteLine($"{hour}:{minute} hours after the start");
                }
            }
        }
    }
}