Back into 30 minutes

using System;

    class Program
    {
        private static void Main()
        {
        int hours = int.Parse(Console.ReadLine());
        int minutes = int.Parse(Console.ReadLine());

        minutes += 30;

        if (minutes > 59)
        {
            hours += 1;
            minutes -= 60;
        }
        if (hours == 24)
        {
            hours = 0;
        }
        Console.WriteLine($"{hours}:{minutes:d2}");

        }
    }