15 minutes

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

namespace ConsoleApplication9
{
    class Program
    {
        static void Main(string[] args)
        {
            int hour= int.Parse(Console.ReadLine());
            int min= int.Parse(Console.ReadLine());




            min = min + 15;
          if( min >= 60)
            {
                min -= 60;
                hour++;
            }
          if( hour >=24)
            {
                hour -= 24;
            }
          //if( hour > 23 && min > 59)
           // {
          //      hour = 0;
          //  }

            if(min < 10)
            {
                Console.WriteLine("{0}:0{1}",hour,min);
            }
            else
            {
                Console.WriteLine("{0}:{1}",hour,min);
            }






        }
    }
}