<?xml version="1.0"?>

<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0">

<xsl:output method="xml"/>

<!-- query for instructors who teach CPS 444 or CPS 445 -->
<xsl:template match="*">
   <xsl:copy>
      <xsl:apply-templates/>
   </xsl:copy>
</xsl:template>

<xsl:template match="instructor[contains(@teaches, '444')] |
                     instructor[contains(@teaches, '445')]">
   <xsl:copy>
      <xsl:apply-templates/>
   </xsl:copy>
</xsl:template>

<xsl:template match="instructor"/>

<xsl:template match="course"/>

</xsl:stylesheet>