Get the first <ul> outside of the tree (but nor parent)

Here is my HTML structure:

<ul class="ul-main">
    <li>James</li>
    <ul class="ul-sub">
              <li>Joyce</li>   
              <li class="widget_subpages_current_page">Randi</li>   
    </ul>
    <li>John</li>
    <li>David</li>
</ul>

HTML:

And now I need to addClass('current-li-main') class to the first <li> element top in hierarchy where widget_subpages_current_page class is. So, it will be <li class="current-li-main">James</li>


So, the result will be:

<ul class="ul-main">
    <li class="current-li-main">James</li>
    <ul class="ul-sub">
              <li>Joyce</li>   
              <li class="widget_subpages_current_page">Randi</li>   
    </ul>
    <li>John</li>
    <li>David</li>
</ul>

HTML:

How will this jQuery code look like?

 

Solution:

jQuery('.ul-main li').eq(0).addClass('current-li-main');

Code (markup):

Regards!