$unique_ids = scalar(grep {defined $_} @normal_array);

##</code><code>##

     %HoA = (
    flintstones => [ "fred", "barney","barney", "nick", "john", "barney" ],
    jetsons => [ "george", "jane", "elroy", "mike", "elias" ],
    simpsons => [ "homer", "marge", "bart", "jack", "homer" ],
    );