SumSeconds

using System;
class SumSeconds
{
    static void Main(string[] args)
    {
        int num1 = int.Parse(Console.ReadLine());
        int num2 = int.Parse(Console.ReadLine());
        int num3 = int.Parse(Console.ReadLine());
        int sec = num1 + num2 + num3;
        int minutes = sec / 60;
        sec = sec % 60;
        Console.WriteLine("{0}:{1}", minutes, sec.ToString().PadLeft(2, '0'));

    }
}