#!/usr/bin/perl
use warnings;
use strict;

use XML::LibXML;

my $dom = XML::LibXML->load_xml(string => << '__XML__');
<Article> <!-- fixed typo -->
  <Main>
   <Sect>
     <H4>Include</H4>
      .....
      <P1> This is the criteria</P1>
      <L>
        <LI>
          <LI_Label>1.</LI_Label>
          <LI_Title>Critera 1</LI_Title>
         </LI>
         <LI>
          <LI_Label>2.</LI_Label>
          <LI_Title>Critera 2</LI_Title>
         </LI>
          <LI>
          <LI_Label>3.</LI_Label>
          <LI_Title>Critera 3</LI_Title>
         </LI>
          <LI>
          <LI_Label>4.</LI_Label>
          <LI_Title>Critera 3</LI_Title>
         </LI>
        </L> <!-- fixed missing closing tag -->
        </Sect>
     </Main>
   </Article>
__XML__

my $xc = XML::LibXML::XPathContext->new;

my $count = $xc->findvalue('count(//Article//Sect//LI)', $dom);
print "$count list nodes found.\n" if $count;