Removing subdirectories from URL

Hi there,

I recently run into an issue with subdirectories.

I would like to make from this structure:
https://www.site.com/newsletter/category/post

..following:
https://www.site.com/post

The category and post slugs will be always different, the only slug that stays the same is /newsletter.

I tried following setup:
Source URL: /newsletter/(.*)/(.*)
Target URL: /$2

But it does not work. Do you have any idea what could be wrong? Is there any problem with second parameter?

Thanks!
Petr

https://www.ads-software.com/plugins/redirection/