Activate page

Hi,

When a user activate an account via email link like

https://mywebsite.org/activate/3ONWPmBo9srNbF4Fm8d6kIQInFV9NvHt/

the browser show https://mywebsite.org/activate/ (width an 302 redirect). All work fine.

But how can I read the value of the activation key (3ONWPmBo9srNbF4Fm8d6kIQInFV9NvHt in my example) in the page activate.php, in order to redirect user to a paiement page ? I want the user ID.

Thanks

The page I need help with: [log in to see the link]