Contribution #308

Problem: ru/3.1.12

Added 3.1.1 3.1.2 3.1.3 3.1.5 3.1.6 3.1.7 3.1.8* 3.1.9 3.1.10* 3.1.11 3.1.12 3.1.15 3.1.16 3.1.17

Editor: Aliaksandr Melnichenka ( @astrosander )

Time: October 20, 2023 at 06:50 AM

+255 -49 lines changed