sub test {
    my ($array1ref, $array2ref) = @_;
    my @array1 = @$array1ref;
    my @array2 = @$array2ref;

    my $count = 0;
    for my $idx (0 .. $#array1) {
        $count++ if shift @array1 eq shift @array2;
    }
    return $count
}