Count number of specific child templates

Case 1

<?xml version='1.0'?>
<?xml-stylesheet href="service1.xsl" type="text/xsl"?>

<parameters>
    <service1>
          <label>first parameter</label>
          <desc>specify machine name</desc>
    </service1>
    <service1>
          <label>second parameter</label>
          <desc>specify machine IP</desc>
    </service1>
    <cmd> -p args1 -t args2 </cmd>
</parameters>

XSL variable should give me value 2 as there are 2 'service1' templates.

Case 2

<?xml version='1.0'?>
<?xml-stylesheet href="service1.xsl" type="text/xsl"?>

<parameters>
    <service2>
          <label>first parameter</label>
          <desc>specify machine name</desc>
    </service2>
    <service2>
          <label>second parameter</label>
          <desc>specify machine IP</desc>
    </service2>
    <service2>
          <label>third parameter</label>
          <desc>specify third param. as Y or N</desc>
    </service2>
    <service2>
          <label>forth parameter</label>
          <desc>specify forth param between 1 to 100</desc>
    </service2>
     <cmd> --name args1 --value args2 --decision args3 --percentage args4</cmd>
</parameters>

XSL variable should give me value 4 as there are 4 'service2' templates.

I am using perl:libxslt processor and using XSL version 1.0.I want xsl
command for giving desired outputs in both cases above,
So,how can I count total number of "service<no.>" templates above
using XSL variable(or any other xsl feature)?
So that I will get total number of arguments for each service.
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Thanks and Regards,
Himanshu Padmanabhi