using System;

public class Program

{

    public static void Main()

    {

        long yourDateTicks  = DateTime.Now.Ticks;

​

        int day = new DateTime(yourDateTicks).Day;

        int month = new DateTime(yourDateTicks).Month;

        int year = new DateTime(yourDateTicks).Year;

        int bcYear = year - 543;

        DateTime bcDate = new DateTime(bcYear, month, day);

        String bcDateFormat = bcDate .ToString("yyyy-MM-dd");

        Console.WriteLine(bcDateFormat);

    }

}