print Dumper(\%categories);
foreach $top ( sort keys %categories){
    if($top =~ /^\s*$/){$top="<blank>";}
    print "$top\n";
    foreach $second ( sort keys %{$categories{$top}}){
       if($second  =~ /^\s*$/){$second="<blank>";}
       print "...$second\n";
       foreach $third (sort keys %{$categories{$top}{$second}}){
        if($third  =~ /^\s*$/){$third="<blank>";}
           print "......$third\n";
       }
    }
}