How to set autoexpunge rule for single user mailbox in dovecot conf?

I need to set autoexpunge rule only for one single user and one mailbox (mail folder), so apply it only for user alice@example.com mailbox INBOX. How can I set namespace in dovecot config, that will apply only to single user?

-- Best regards, Alexey Murz Korepov. Email, Jabber: murznn@gmail.com