using System;

public class Program

{

    public static void Main()

    {

        var eventDate = DateTimeOffset.Parse("2025-06-28T12:00:00.000+09:00");

        var before90 = eventDate.AddDays(-90);

        var before91 = eventDate.AddDays(-91);

        var before60 = eventDate.AddDays(-60);

​

        Console.WriteLine($"Event Date: {eventDate}");

        Console.WriteLine($"90 Days before: {before90}");

        Console.WriteLine($"91 Days before: {before91}");

        Console.WriteLine($"60 Days before: {before60}");

    }

}