using System;

using Quartz;

public class Program

{

    public static void Main()

    {

        String exp = "0 0 0 1 1 ? 3000";

        exp = "59 59 23 31 12 ? 2130";

        bool valid = CronExpression.IsValidExpression(exp);

        Console.WriteLine(valid);

        if (valid) {

            var cronExpression = new CronExpression(exp);

            valid = cronExpression.GetNextValidTimeAfter(DateTimeOffset.Now) != null;

        }

        Console.WriteLine("Can I use <" + exp + ">? " + (valid ? "Go ahead!" : "This shall fail."));

    }

}