Ruises to various ports.
* Ship W left at 4:00 PM on Sunday, December 22, for a series of 8-days cruises to Mandva.
* Ship X left at 4:30 PM on Sunday, December 22, for a series of alternating 11-days and 13-days cruises to Alibaug.
* Ship Y left at 5:00 PM on Sunday, December 22, for a series of 5-days cruises to Khihim.
* Ship Z left on Monday for a series of 7-days cruises. Each ship is scheduled to return back early in the morning after the
last day of the cruise and leave again late in the afternoon of the same day.
On how many days occasions between December 22 and February 28 will three ships be moored at the port?