using System;

public class Program

{

    public static void Main()

    {   

        DateTime minhaData = new DateTime(2019, 3, 25);

        int timestamp = DatetimeToUnixTimestamp(minhaData);

        Console.WriteLine(timestamp);

        Console.WriteLine(UnixTimestampToDateTime(timestamp).ToString());

    }

    public static int DatetimeToUnixTimestamp(DateTime datahora){

        return (Int32)(DateTime.UtcNow.Subtract(new DateTime(1970, 1, 1))).TotalSeconds;

    }

    public static DateTime UnixTimestampToDateTime(int timestamp)

    {

        DateTime dateTime = new System.DateTime(1970, 1, 1, 0, 0, 0, 0);

        return dateTime.AddSeconds(timestamp);

    }

}