function reverse_name($str){
    $len = mb_strlen($str, 'UTF-8');
    $result = [];
    for ($i = 0; $i < $len; $i++) {
        $result[] = mb_substr($str, $i, 1, 'UTF-8');
    }
    $result = array_reverse($result);
    $result = implode("",$result);
    return $result;
}