Time + 15 Minutes

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Time_plus_15_Minutes
{
    class Program
    {
        static void Main(string[] args)
        {
            var hours = int.Parse(Console.ReadLine());
            var mins = int.Parse(Console.ReadLine());

            int new_Time = mins + 15;

            if (new_Time > 59)
            {
                hours += 1;
                new_Time -= 60;
                if (hours > 23 && new_Time > 9)
                {
                    Console.WriteLine(0 + ":" + new_Time);
                }
                else if (hours > 23 && new_Time < 10)
                {
                    Console.WriteLine(0 + ":" + 0 + new_Time);
                }
            }
            else
            {
                Console.WriteLine(hours + ":" + new_Time);
            }
        }
    }
}