> For the complete documentation index, see [llms.txt](https://nghiengym.nghienplus.net/loi-gioi-thieu/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://nghiengym.nghienplus.net/loi-gioi-thieu/loi-gioi-thieu.md).

# Lời giới thiệu

Tại sao