BeerTimeTernery.cs

using System;

class Program
{
    private static void Main()
    {
        string input = Console.ReadLine();

        try
        {
            DateTime date = DateTime.Parse(input);
            Console.WriteLine((date.Hour >= 13 || date.Hour < 3) ? "beer time" : "non-beer time");
        }
        catch (FormatException)
        {
            Console.WriteLine("invalid time");
        }
    }
}