start mutt with mailbox with unread mail opened

[tannhauser <tannhauser@xxxxxxxxxxxxx>]

hello *,

since version 1.5.16, there's a new command <next-unread-mailbox>
to open the -well, you guessed it- next mailbox with unread messages. 
Has anyone an idea how i could start mutt and it automatically opens the
first mailbox with unread messages?

th