Filter Problem

[Kenny Chong]

i have three identical filter

first:
(&(|(mail=a*)(givenName=a*))(objectClass=inetOrgPerson))
second:
(&(objectClass=inetOrgPerson)(|(mail=a*)(givenName=a*)))

third:
(|(&(objectClass=inetOrgPerson)(mail=a*)(&(objectClass=inetOrgPerson)(givenName=a*))

however, the first filter i didn't get any result, but the second and third 
filter i get what i want.

anyone know what is the problem with the first filter? the entries i want to 
search for contains all the three attribute (mail, givenName, objectClass)