Counting messages in a mailbox

Hi.

I'd like to be able to count the number of messages in a mailbox.
The simple-minded approaches, such as:
        egrep -i '^From ' mailbox | wc -l
        egrep -i '^Subject:' mailbox | wc -l
don't work for fairly obvious reasons.

This seems to work:
        formail -s formail -X 'From ' < mailbox | wc -l
but due to the number of processes, it's *very* slow.

Is there a better way?

Thanks,
Stan Ryckman (stanr(_at_)tiac(_dot_)net)