How to find non system user in oracle?.

In dba_users there is a column ORACLE_MAINTAINED
if the value of this column is N then the user is created manually and its not created by oracle.

ex: below users are non oracle users created manually. which are not displayed here are all created by oracle while creating database.

SQL> select USERNAME from dba_users where ORACLE_MAINTAINED ='N';

USERNAME
--------------------------------------------------------------------------------
GITION
MTA
G2AC20
LAB_RITY
CRED20
MONITOR
SKELSR