Under the Julian calendar system, the year averages to 365.25 days after 4 years. In the Gregorian system, determine the average length of the year after 400 years. If a country needed to convert from...

Under the Julian calendar system, the year averages to 365.25 days after 4 years. In the Gregorian system, determine the average length of the year after 400 years. If a country needed to convert from the Julian to the Gregorian calendar now, how many days would it need to remove from the calendar?