Operators: Or/And

In my logic I do not want to send a message out when the doc types DO NOT EQUAL either 'AB' 'AN' 'ICLP' 'LU'.

I always get confused betweeen 'OR' and 'AND'

My logic: Is it right? Is there a better way to write the code?

if i_ekko-bsart NE 'AB' or

i_ekko-bsart NE 'AN' or

i_ekko-bsart NE 'ICLP' or

i_ekko-bsart NE 'LU'.

MESSAGE E054(ZS) WITH 'Message out here'

endif.

Thank-You