HTMLify

class Solution {

    /**
     * @param Integer[] $arr
     * @return Integer
     */
    function findLucky($arr) {
        $a = [];
        $fq = array_count_values($arr);
        foreach($fq as $f => $k){
            if($f == $k){
                $a[] = $f;
            }
        }
        if(empty($a)) return -1;
        else return max($a);
    }
}