static void Main(string[] args)
{
random = new Random();
my_countdown = new MyCountdownEvent(students.Length);
Console.WriteLine("Son las 7:55 am. Va a empezar la clase.");
Console.WriteLine();
new Thread(() => ArrivePeople()).Start();
my_countdown.Wait();
Console.WriteLine();
Console.WriteLine("8:00 am!!! Empieza la clase.");
}
