using System;

public class Program

{

    public static void Main()

    {

        //DateTime timestamp = DateTime.FromFileTime(124324234223465436);

        DateTime timestamp = DateTime.Parse("2025-03-08 11:44:59");

        Console.WriteLine(timestamp);

        Console.WriteLine(timestamp.AddMinutes(-timestamp.Minute % 15).AddSeconds(-timestamp.Second));

        Console.WriteLine(timestamp.AddMinutes(-(timestamp.Minute % 15)).AddSeconds(-timestamp.Second));

    }

}