Time + 15 Minutes

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

namespace HourPlus15Minutes
{
    class TimePlus15
    {
        static void Main(string[] args)
        {
            int hour = int.Parse(Console.ReadLine());
            int minutes = int.Parse(Console.ReadLine());
            int addminutes = minutes + 15;
            if (addminutes > 59)
            {
                hour++;
                addminutes -= 60;
                if (hour > 23)
                {
                    hour = 0;
                }
                Console.WriteLine("{0}:{1:00}", hour,addminutes);
            }
            else
            {
                Console.WriteLine("{0}:{1:00}",hour,addminutes);
            }
        }
    }
}