redirect 301 country subfolder to frontpage

i look for a redirect pattern which redirects all URLs with the slug /at/ to the frontpage of my site.

example:

https://www.example.com/at/shop/systeme/alf/product.html

should redirect to:

https://www.example.com/de/shop/ (this is my frontpage)

i have hundrets of urls with /at/ in the slug. All these Urls should redirect (301) to https://www.example.com/de/shop/

i hope somebody can help me

best regards

Tom