newbie question: which objectClass?

["Stefano Zanmarchi" <zanmarchi@gmail.com>]

Hi,
I'd like to set up a minimal ldap server just for authentication
(bind) purposes.
No attributes need to be stored apart from uid and userPassword.
I'd like to insert entries like

   dn: uid=john.smith@myorg.com,ou=people,dc=myorg,dc=com
   objectClass: ?????
   uid: john.smith@myorg.com
   userPassword: secret

(If I use objectClass: inetOrgPerson I need to enter cn and sn as
well, which I don't wont)

Can I achieve this?
Thanks a lot,
Stefano