Two.

OOO C OOOOO C OOOOOOOOOOO

(where Os are chained unbroken links, and the Cs are the unchained broken links)

And equivalently

OOO C OOOOOO C OOOOOOOOOO

lib/DbaDatabase.php:134: Warning: dba_replace() [<a href='function.dba-replace'>function.dba-replace</a>]: You cannot perform a modification to a database without proper access