How do i prevent users/registrations from entering a number in the "Location" Feild?
 

Hi all i have set my registration and profile update to require a user to enter a location, however this is being bypassed by bots/users entering a 1, how do i prevent them entering any digits and force entries with more than 2 letters?

I see there is soething there for regular expressions but know absolutely nothing about them or how to configure them...can someone help?