List category and subcategory in magento

I found below code to list category and subcategory . I can put it everywhere in your website.

$rootcatId= Mage::app()->getStore()->getRootCategoryId();
$categories = Mage::getModel('catalog/category')->getCategories($rootcatId);
function  get_categories($categories) {
    $array= '
';
    foreach($categories as $category) {
        $cat = Mage::getModel('catalog/category')->load($category->getId());
        $count = $cat->getProductCount();
        $array .= '
'.
        '' .
                  $category->getName() . "(".$count.")\n";
        if($category->hasChildren()) {
            $children = Mage::getModel('catalog/category')->getCategories($category->getId());
             $array .=  get_categories($children);
            }
         $array .= '
';
    }
    return  $array . '
';
}
echo  get_categories($categories); ?>