function prob($data) {
        $best = -1000000;
        if ( count($data) < 2 ) return count($data) == 0 ? 0 : $data[0];
        for ( $i = 0; $i < count($data); ++$i ) {
                $d = $data;
                unset($d[$i],$d[$i+1],$d[$i-1]);
                if (($b = prob(array_values($d)) + $data[$i]) > $best ) $best = $b;
        }
        return $best;
}