function equalizeArray($arr) {
    $counter = [];
    $max = [];
    foreach ($arr as $el) {
        isset($counter[$el]) ? $counter[$el]++ : $counter[$el] = 1;
        if ($counter[$el] > $max['value']) {
            $max['value'] = $counter[$el];
            $max['index'] = $el;
        }
    }
    
    unset($counter[$max['index']]);
    return array_sum($counter);
}