Trouble configuring drupal path:wildcard

I'm attempting to use the drupal path:wildcard theme switching rule, using either the "contains" operator ('*') or the regex operator ('~').

The URLs that I want to display using a special theme are all in the form: menu-instructor-agm-, like:
menu-instructor-agm
menu-instructor-agm-2014
menu-instructor-agm-2013

and so on ...

The UI exposes two fields aside from the operator for me to fill in, per the image below:

What I'm trying to figure out is what to put into the first empty box so that ThemeKey will switch themes if it finds the string 'menu-instructor-agm' .... I've tried the '~' operator as well, with a variety of regular expressions (/^menu-instructor-agm/ /*menu-instructor*/ and so on ...) to no avail.