calculate the maximum number of nodes

i want to calculate the maximum number of <keyword> in <products>
how can i do it and i want the reference of the maximum number of <keyword>
for another task.
the task is reference to the following xml:
<?xml version="1.0" standalone="no"?>
<!DOCTYPE HUBSHOPXML SYSTEM "HUBSHOPXML.DTD">
<!-- <?xml-stylesheet type="text/xsl" href="HubShopAsciiProductXSL.xsl"?>
-->
<!-- ADDED xmllang="en" to PRODUCT and ARTICLE on 24-05-2001 by TPR, (PDE)
-->
<HUBSHOPXML>
  <SUPPLIER>
    <COMPANYID QUALIFIER="TRA">12345</COMPANYID>
    <COMPANYNAME>Test Company</COMPANYNAME>
  </SUPPLIER>
  <PRODUCTS>
    <PRODUCT xmllang="en">
      <ACTION>A</ACTION>
      <PRODUCTID QUALIFIER="mk">1234</PRODUCTID>
	  <MANUFACTURER>
	  	<MANUFACTURERNAME>Test Company</MANUFACTURERNAME>
	  </MANUFACTURER>
      <PRODUCTNAME xmllang="en">Product name</PRODUCTNAME>
      <BRANDNAME xmllang="en">BrandName</BRANDNAME>
      <MANUFACTURERPRODUCTNAME xmllang="no">Producents produkt
navn</MANUFACTURERPRODUCTNAME>
      <EXTRAIDLIST>
        <ID QUALIFIER="ab">2345</ID>
        <ID QUALIFIER="ac">4567</ID>
        <ID QUALIFIER="ad">6789</ID>
      </EXTRAIDLIST>
      <REPLACEDPRODUCTID QUALIFIER="mk">2345</REPLACEDPRODUCTID>
      <AVAILABLEFROM>20000210</AVAILABLEFROM>
      <AVAILABLETO>20001231</AVAILABLETO>
      <FIRSTREGISTERED>20000205</FIRSTREGISTERED>
      <LASTMODIFIED>20000208</LASTMODIFIED>
      <PRODUCTTEXT xmllang="en">This is a text</PRODUCTTEXT>
      <PRODUCTTEXT xmllang="no">Dette er en tekst</PRODUCTTEXT>
      <KEYWORDLIST>
        <KEYWORD xmllang="en">Keyword 1</KEYWORD>
        <KEYWORD xmllang="no">Sokeord 1</KEYWORD>
        <KEYWORD xmllang="no">Sokeord 2</KEYWORD>
        <KEYWORD xmllang="no">Sokeord 3</KEYWORD>
      </KEYWORDLIST>
      <STORAGE xmllang="en">Storage</STORAGE>
      <STORAGE xmllang="no">Lagring</STORAGE>
      <KEEPING xmllang="en">Keeping</KEEPING>
      <KEEPING xmllang="no">Oppbevaring</KEEPING>
      <STANDARDLIST>
        <STANDARD xmllang="en" QUALIFIER="mgr">Standard 1</STANDARD>
        <STANDARD xmllang="en" QUALIFIER="cpn">Standard 2</STANDARD>
        <STANDARD xmllang="no" QUALIFIER="mgr">Standard 1</STANDARD>
        <STANDARD xmllang="no" QUALIFIER="cpn">Standard 3</STANDARD>
      </STANDARDLIST>
      <BLOBLIST>
        <BLOB>
          <BLOBNAME>Bilde.jpg</BLOBNAME>
          <BLOBTYPE EXTENSION="JPG">JPG BILDE</BLOBTYPE>
        </BLOB>
      </BLOBLIST>
      <PRODUCTGROUPS>
        <PRODUCTGROUP PRIMARY="Y">
          <PRODUCTGROUPID QUALIFIER="TRA">123456789</PRODUCTGROUPID>
          <PRODUCTGROUPNAME xmllang="no">Produktgruppe
123456789</PRODUCTGROUPNAME>
          <PRODUCTGROUPNAME xmllang="se">Produktgrups
123456789</PRODUCTGROUPNAME>
        </PRODUCTGROUP>
        <PRODUCTGROUP PRIMARY="N">
          <PRODUCTGROUPID QUALIFIER="ISO">12</PRODUCTGROUPID>
          <PRODUCTGROUPNAME xmllang="no">Produktgruppe 12</PRODUCTGROUPNAME>
          <PRODUCTGROUPNAME xmllang="se">Produktgrups 12</PRODUCTGROUPNAME>
          <PRODUCTGROUPNAME xmllang="en">Productgroup 12</PRODUCTGROUPNAME>
        </PRODUCTGROUP>
      </PRODUCTGROUPS>
      <URLLIST>
        <URL>
          <URLADR>http://www.hubshop.com</URLADR>
          <URLDESC xmllang="no">Hjemmesiden til Hubshop></URLDESC>
          <URLDESC xmllang="en">Homepage for Hubshop></URLDESC>
        </URL>
        <URL>
          <URLADR>http://www.hubshop.org</URLADR>
          <URLDESC xmllang="no">Testsiden til Hubshop></URLDESC>
          <URLDESC xmllang="en">Testpage for Hubshop></URLDESC>
        </URL>
      </URLLIST>
    </PRODUCT>
    <PRODUCT xmllang="en">
      <ACTION>A</ACTION>
      <PRODUCTID QUALIFIER="mk">5678</PRODUCTID>
	  <MANUFACTURER>
	  	<MANUFACTURERNAME>Test Company</MANUFACTURERNAME>
	  </MANUFACTURER>
	  <PRODUCTNAME xmllang="en">Product name 2</PRODUCTNAME>
      <PRODUCTNAME xmllang="no">Produkt navn 2</PRODUCTNAME>
     <KEYWORDLIST>
        <KEYWORD xmllang="no">Sokeord 2</KEYWORD>
        <KEYWORD xmllang="no">Sokeord 3</KEYWORD>
      </KEYWORDLIST>      
    </PRODUCT>
    <PRODUCT xmllang="en">
      <ACTION>A</ACTION>
      <PRODUCTID QUALIFIER="ee">5678</PRODUCTID>
	  <MANUFACTURER>
	  	<MANUFACTURERNAME>Test Company</MANUFACTURERNAME>
	  </MANUFACTURER>
	  <PRODUCTNAME xmllang="en">Product name 2</PRODUCTNAME>
      <PRODUCTNAME xmllang="no">Produkt navn 2</PRODUCTNAME>
     <KEYWORDLIST>
        <KEYWORD xmllang="no">Sokeord 2</KEYWORD>
        <KEYWORD xmllang="no">Sokeord 3</KEYWORD>
        <KEYWORD xmllang="no">Sokeord 2</KEYWORD>
       
      </KEYWORDLIST>      
    </PRODUCT>
  </PRODUCTS>
  </HUBSHOPXML>

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