using System;

public class Program

{

    public static void Main()

    {

        //Your code goes here

        string firstTime = Console.ReadLine();

        string secondTime = Console.ReadLine();

        string thirdTime = Console.ReadLine();

        int minute = 60;

        int seconds = Int32.Parse(firstTime)  + Int32.Parse(secondTime) + Int32.Parse(thirdTime);

        int minutes = seconds/minute;

        int remainderSeconds = seconds%minute;

        Console.WriteLine("{0}:{1}", minutes.ToString(), remainderSeconds.ToString("D2"));

    }

}