Contribution #629

Problem: ru/8.4.12

Added 8.4.1 8.4.12

Editor: Aliaksandr Melnichenka ( @astrosander )

Time: November 17, 2023 at 07:32 PM

GitHub commit: 4e639508f7319496fecfff1e8fdc06206763da05

+243 -49 lines changed