Why can't you do this:

$idx = index($string, '(') + 1;
$num = substr($string, $idx, length($string) - $idx - 1);
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Or:

($num) = $string =~ /\((\d+)\)/;

# Plus the year

($year, $num) = $string =~ /(\d+)[^(]*\((\d+)\)/;
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