Xpath to get a portion of matched text directly in C#

I have a html whose portion looks like this:


<li id="SalesRank">
<b>Amazon Best Sellers Rank:</b> 

#841,219 in Music (<a href="http://ift.tt/1FdxPiZ">See Top 100 in Music</a>)

</li>

I wanted to extract 841,219 using a single Xpath (Without Linq or processing nodes coming out of the Xpath in a loop)

Obviously, getting to the li element is easy: Dim node As HtmlNode = x.DocumentNode.SelectSingleNode("//li[@id=""SalesRank""]")

After this I am not sure what to put in the Xpath to "extract" the number and have it in node

Any ideas would be appreciated. C# or Vb.net can be the language.