Author: 斎藤信
Reviewer: 2333

  At the end of the previous article, we learned that there will be no leap first month until at least 2060, so do not expect a two-month winter holiday. This year was purely an exception, though. Why is that? The end of the previous article offers a hint, but readers can think about it for themselves first.

  Have a wonderful start to the new semester (runs away