using static System.Console;
namespace App
{
    class Prog
    {
        static void Main()
        {
            var x = int.Parse(ReadLine());
            x = x / 5 * 3;
            string min;
            if (x % 60 == 0) min = "00";
            else min = (x % 60).ToString();
            if (min.Length == 1) min = "0" + min;
            WriteLine(10 + (x / 60) + ":" + min);
        }
    }
}