using System;

class Program
{
    static void Main()
    {
        int m1 = int.Parse(Console.ReadLine());
        int m2 = int.Parse(Console.ReadLine());
        int m3 = int.Parse(Console.ReadLine());

        int sum = m1 + m2 + m3;
        int minutes = sum / 60;
        int seconds = sum % 60;

        if(seconds<10)
        {
            Console.WriteLine("{0}:0{1}", minutes, seconds);

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

        }

    }
}