# solution 2, using text:csv_xs
use Text::CSV_XS;
my $csv = Text::CSV_XS->new();
$count=0;

my $file = 'PS0002_9_2006b.txt';
if (defined $ARGV[0]) {
    $file = $ARGV[0];
}
 
my $sum = 0;
open(my $data, '<', $file) or die "Could not open '$file'\n";
while (my $line = <$data>) {
    chomp $line;
    exit if ($count >= 20);
    $count++;
    if ($csv->parse($line)) {
        my @columns = $csv->fields();

        $sum += $columns[2];
    } else {
        warn "Line could not be parsed: $line\n";
    }
}
print "$sum\n";
# end solution 2_______________________