using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Convert");

        long unixTime = 1683158400000;

        unixTime = unixTime / 1000;

        DateTime date = DateTimeOffset.FromUnixTimeSeconds(unixTime).UtcDateTime;

        Console.WriteLine(date.ToString("yyyy-MM-dd HH:mm:ss"));

        unixTime = 1683072000000;

        unixTime = unixTime / 1000;

        date = DateTimeOffset.FromUnixTimeSeconds(unixTime).UtcDateTime;

        Console.WriteLine(date.ToString("yyyy-MM-dd HH:mm:ss"));

    }

}