using System;

namespace seconds_calc
{
    class Program
    {
        static void Main(string[] args)
        {
            int time1 = int.Parse(Console.ReadLine());
            int time2 = int.Parse(Console.ReadLine());
            int time3 = int.Parse(Console.ReadLine());

            int totaltime = time1 + time2 + time3;

            int minutes = totaltime / 60;
            int seconds = totaltime % 60;

            if (seconds < 10)

            {
                Console.WriteLine("{0}:0{1}", minutes, seconds);
            }

            else

            {
                Console.WriteLine("{0}:{1}", minutes, seconds);
            }
        }
    }
}