Processing Instructions

Hi everybody!!!
Can anybody let me know about the mistake I am doing!!

XSL
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="2.0">
<xsl:template match="*">
  <xsl:if
    test="@pg and (not(preceding::*[1]/@pg)
      or @pg != preceding::*[1]/@pg)">
    <xsl:processing-instruction name="p">
      <xsl:value-of select="@pg"/>
    </xsl:processing-instruction>
  </xsl:if>
  <xsl:element name="{local-name()}">
    <xsl:apply-templates select="node()"/>
  </xsl:element>
</xsl:template>
<xsl:template match="@pg"/>
</xsl:stylesheet>

Input
<ch pg="1">
<p pg="1">1</p>
<p pg="1">2<s pg="1">3</s>4</p>
<p pg="1">5</p>
<p pg="1">6<s pg="2">7</s>8</p>
<p pg="2">9</p>
<p pg="2">10</p>
<p pg="2">11</p>
<p pg="2">12<m pg="3">13<s pg="3">14</s></m>15</p>
</ch>

XSLT Result
<?p 1?><ch>
<?p 1?><p>1</p>
<p>2<s>3</s>4</p>
<p>5</p>
<p>6<?p 2?><s>7</s>8</p>
<p>9</p>
<p>10</p>
<p>11</p>
<p>12<?p 3?><m>13<?p 3?><s>14</s></m>15</p>
</ch>