Примерен вход и изход

using System;

namespace tESt
{
    class Program
    {
        static void Main(string[] args)
        {

            var hourExamen = int.Parse(Console.ReadLine());
            var minExamen = int.Parse(Console.ReadLine());
            var hourArrive = int.Parse(Console.ReadLine());
            var minArrive = int.Parse(Console.ReadLine());

            var hourExamenToMin = hourExamen * 60;
            var timeExamen = minExamen + hourExamenToMin;

            var timeExamenEarly30 = timeExamen - 30;

            var hourArriveToMin = hourArrive * 60;
            var timeArrive = minArrive + hourArriveToMin;

            var minDifference = Math.Abs(timeExamen - timeArrive);
            var hourDifference = minDifference / 60;
            var minDifferenceB = minDifference % 60;



            if (timeArrive < timeExamenEarly30)
            {
                Console.WriteLine("Early");

                if (hourDifference < 1)
                {
                    Console.WriteLine($"{minDifferenceB} minutes before the start");
                }
                else
                {
                    Console.WriteLine($"{hourDifference}:{minDifferenceB:d2} hours before");
                }
            }

            else if (timeArrive > timeExamen)
            {
                Console.WriteLine("Late");

                if (hourDifference < 1)
                {
                    Console.WriteLine($"{minDifferenceB} minutes after the start");
                }
                else
                {
                    Console.WriteLine($"{hourDifference}:{minDifferenceB:d2} hours after");
                }
            }

            else if (timeArrive == timeExamen)
            {
                Console.WriteLine("On time");
            }

            else if (timeExamenEarly30 < timeArrive || timeArrive < timeExamen)
            {
                Console.WriteLine("On time");

                if (hourDifference < 1)
                {
                    Console.WriteLine($"On time {minDifferenceB} minutes before the start");
                }
                else
                {
                    Console.WriteLine($"On time{hourDifference}:{minDifferenceB:d2} hours before");
                }

            } else
            {
                Console.WriteLine("Error!");
            }

        }
    }
}