Time15Minutes

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

namespace _09.Time_15Minutes
{
    class Program
    {
        static void Main(string[] args)
        {
            var hour = int.Parse(Console.ReadLine());
            var min = int.Parse(Console.ReadLine());

            var sum = ((hour * 60) + min + 15);
            var resulthour = sum / 60;
            if (resulthour >= 24)
            {
                resulthour -= 24;
            }
            var resultmin = sum % 60;

            Console.WriteLine("{0}:{1:00}", resulthour, resultmin);
        }
    }
}