public function run()
    {
        $header = $this->rec->header();
        $messages = $header->messages;
        $instructions = $messages->instructions;
        $lines = explode("\n", $instructions);
        foreach ($lines as $line) {
            // We don't know what language the game was played in, so we try
            // every language we know.
            foreach ($this->mapTypeRegexes as $rx) {
                $matches = [];
                if (preg_match($rx, $line, $matches)) {
                    return $matches[1];
                }
            }
        }
    }