Time + 15 Minutes

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

namespace ConsoleApplication58
{
    class Program
    {
        static void Main(string[] args)
        {
          var hour = int.Parse(Console.ReadLine());
         var minutes = int.Parse(Console.ReadLine());

         TimeSpan times = new TimeSpan(hour, minutes, 0);
         TimeSpan times2 = new TimeSpan(0, 15, 0);
         TimeSpan sumaTime = times + times2;

        Console.WriteLine("{0:h\\:mm}", sumaTime);
        }
     }
}