Time + 15

using System;
class Program
{
    static void Main()
    {
        int h = int.Parse(Console.ReadLine());
        int m = int.Parse(Console.ReadLine());
        m = m + 15;

        if (m < 10)
        {
            Console.WriteLine(h + ":0" + m);
        }
        else if (m >= 60)
        {
            h = h + 1;
            m = m - 60;
            if (h > 24 && m >= 1 && m <= 9)
            {
                h = h - 24;
                Console.WriteLine("{0}:0{1}", h, m);
            }
            else if (h >= 24 && m >= 10)
            {
                h = h - 24;
                Console.WriteLine("{0}:{1}", h, m);
            }
            else if (h == 24 && m == 0)
            {
                Console.WriteLine("0:00");
            }
            else if(h == 24 && m >= 1 && m <= 9)
            {

                Console.WriteLine("0:0{0}",m);
            }
            else if (h == 24 && m >= 10)
            {

                Console.WriteLine("0:{0}", m);
            }
            else
            {
                if (m >= 0 && m <= 9)
                {
                    Console.WriteLine(h + ":0" + m);
                }
                else
                {
                    Console.WriteLine(h + ":" + m);
                }
            }

        }
        else if (h > 23)
        {
            h = h % 24;
            Console.WriteLine("{0}:{01:00}", h, m);
        }
        else
        {
            Console.WriteLine("{0}:{1}", h, m);
        }

    }
}