using System;
using static System.Console;
using System.Linq;
using System.Collections.Generic;

class Program
{
    static int NN => int.Parse(ReadLine());
    static int[] NList => ReadLine().Split(':').Select(int.Parse).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var c = NList;
        c[1] += 5;
        if (c[1] >= 60)
        {
            ++c[0];
        }
        c[1] %= 60;
        c[0] %= 24;
        WriteLine($"{c[0]:00}:{c[1]:00}");
    }
}