+15 minutes

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

namespace Time_Plus_15_Minutes
{
    class Program
    {
        static void Main(string[] args)
        {
            int hours = int.Parse(Console.ReadLine());
            int minutes = int.Parse(Console.ReadLine());
            minutes = minutes + 15;
            if(minutes>59)
            {
                if(minutes==60)
                {
                    hours += 1;
                    minutes = 0;
                }
                else
                {
                    hours += 1;
                    minutes = minutes - 60;
                }
            }
            if(hours>23)
            {
                hours = 0;
            }
            Console.WriteLine("{0}:{1:00}",hours,minutes);
        }
    }
}