$i = 1;
foreach ($cikti[0] as $key => $element) {
    $title = $cikti[1][$key];
    if($i>6){
        exit;
    }
    else{
        $content = str_replace($element, '<h'.$i.' id="' . seo($title) . '">' . $title . '</h>', $content);
        $i++;
    }