how to display automatic number position BreadcrumbList Markup with dynamic folder?

Code: Select all
<ol class="breadcrumb" itemscope itemtype="https://schema.org/BreadcrumbList">
<li itemprop="itemListElement" itemscope itemtype="https://schema.org/ListItem">
<a href="<cms:show k_site_link />" title="Home" itemprop="item"><span itemprop="name">Home</span></a>
<meta itemprop="position" content="1" />
</li>

Postion "2" if this parrent folder
Position "2" and "3" if this folder has child

<li itemprop="itemListElement" itemscope itemtype="https://schema.org/ListItem">
<a href="<cms:show k_page_link />" title="<cms:show k_page_title />"><span itemprop="name"><cms:show k_page_title /></span></a>
<meta itemprop="position" content="4" />
</li>
</ol>