using System;

namespace ConsoleApp1
{
    class Program
    {
        static void Main(string[] args)
        {
            decimal startHour = decimal.Parse(Console.ReadLine());
            decimal startMinutes = decimal.Parse(Console.ReadLine());

            decimal arrivalHour = decimal.Parse(Console.ReadLine());
            decimal arrivelMinutes = decimal.Parse(Console.ReadLine());

            decimal hour = Math.Abs(startHour - arrivalHour);
            decimal minutes = Math.Abs(startMinutes - arrivelMinutes);

            Console.WriteLine($"{hour}:{minutes}");
        }
    }
}