03. Time + 15 Minutes

using System;

namespace MinutesPlus15
{
    class Program
    {
        static void Main()
        {
            int hour = int.Parse(Console.ReadLine());
            int minute = int.Parse(Console.ReadLine());
            int result = hour * 60 + minute + 15;
            int totalhour = result / 60;
            int totalminute = result % 60;

            if (totalminute == 0 && totalhour <= 23)
            {
                Console.WriteLine($"{totalhour}:00");
            }
            else if (totalminute == 0 && totalhour >= 24)
            {
                Console.WriteLine($"{totalhour % 24}:00");
            }

            else if (totalminute < 10 && totalhour <=23 )
            {
                Console.WriteLine($"{totalhour}:0{totalminute}");
            }

            else if (totalhour <= 23)
            {
                Console.WriteLine($"{totalhour}:{totalminute}");
            }

            else if (totalhour >= 24 && totalminute < 10)
            {
                Console.WriteLine($"{totalhour % 24}:0{totalminute}");
            }

            else if (totalhour >= 24 && totalminute > 10)
            {
                Console.WriteLine($"{totalhour % 24}:{totalminute}");
            }
        }
    }
}