\documentclass{article}
\usepackage[startNumber=false,footnotes,definitionLists,hashEnumerators,hybrid=true]{markdown}

\begin{document}

\begin{markdown}
_markdown_ use `hybrid=true` can insert \LaTeX code **directly**.

  $x^2$  $x_2$

![](frog.jpg "One picture")

the following `README` comes from [USTC Thesis](https://github.com/ustctug/ustcthesis)。
\end{markdown}

\markdownInput{README.md}

\end{document}
