⇒ December 21 (Saturday) is the day off
⇒ December 23, 24 - normal work schedule
⇒ December 25 (Wednesday) is the day off
⇒ December 26, 27 - normal work schedule
⇒ from December 28 (Saturday) to January 8 (Wednesday) - weekends
⇒ from January 9 (Thursday) - normal work schedule