This is an H1

This is an H2

这是 H1

这是 H2

这是 H6

这是 H1

这是 H2

这是 H3

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consectetuer adipiscing elit. Aliquam hendrerit mi posuere lectus.
Vestibulum enim wisi, viverra nec, fringilla in, laoreet vitae, risus.

Donec sit amet nisl. Aliquam semper ipsum sit amet velit. Suspendisse
id sem consectetuer libero luctus adipiscing.

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consectetuer adipiscing elit. Aliquam hendrerit mi posuere lectus.
Vestibulum enim wisi, viverra nec, fringilla in, laoreet vitae, risus.

Donec sit amet nisl. Aliquam semper ipsum sit amet velit. Suspendisse
id sem consectetuer libero luctus adipiscing.

这是一个标题。

1. 这是第一行列表项。
2. 这是第二行列表项。

给出一些例子代码：

return shell_exec("echo $input | $markdown_script");

• Red
• Green
• Blue

• Red
• Green
• Blue

• Red
• Green
• Blue

1. Bird
2. McHale
3. Parish

<ol>
<li>Bird</li>
<li>McHale</li>
<li>Parish</li>
</ol>

1. Bird
2. McHale
3. Parish
4. Bird
5. McHale
6. Parish

• Lorem ipsum dolor sit amet, consectetuer adipiscing elit.
  Aliquam hendrerit mi posuere lectus. Vestibulum enim wisi,
  viverra nec, fringilla in, laoreet vitae, risus.
• Donec sit amet nisl. Aliquam semper ipsum sit amet velit.
  Suspendisse id sem consectetuer libero luctus adipiscing.

1986. What a great season.

There is a literal backtick (`) here.