On Time for the Exam

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            int HourIzpit = int.Parse(Console.ReadLine());
            int MinIzpit = int.Parse(Console.ReadLine());
            int HourPrist = int.Parse(Console.ReadLine());
            int MinPrist = int.Parse(Console.ReadLine());
            int ObMinIzpit = HourIzpit * 60 + MinIzpit;
            int ObMinPrist = HourPrist * 60 + MinPrist;
            if (ObMinIzpit==ObMinPrist || (ObMinIzpit>ObMinPrist && ObMinIzpit-ObMinPrist<=30))
            {
                Console.WriteLine("On time");
            }
            if (ObMinIzpit > ObMinPrist && ObMinIzpit - ObMinPrist >30)
            {
                Console.WriteLine("Early");
            }
            if (ObMinPrist>ObMinIzpit)
            {
                Console.WriteLine("Late");
            }
            if (Math.Abs(ObMinPrist-ObMinIzpit)!=0)
            {
                var hours = Math.Abs(ObMinPrist - ObMinIzpit) / 60;
                var mins = Math.Abs(ObMinPrist - ObMinIzpit) % 60;
                if (hours >=1)
                {
                    if (mins < 10) Console.Write(hours + ":0" + mins + " hours");
                    else Console.Write(hours + ":" + mins + " hours");
                }
                else Console.Write(mins + " minutes");
                if ((ObMinPrist - ObMinIzpit) < 0)
                    Console.WriteLine(" before the start");
                else
                    Console.WriteLine(" after the start");
            }
        }
    }
}