Extract First node

Hi
I am having a problem with XPath expression for XSLT. I am trying to extract a
node from xml with a special attribute. For example
<a>
  <b>
    <c type="html">HTML file</c>
  </b>
  <b>
    <c type="text">Text File</c>
  </b>
  <b>
    <c type="pdf">First Pdf File</c>
  </b>
  <b>
    <c type="pdf">Second Pdf File</c>
  </b>
  <b>
    <c type="rtf">Rtf File</c>
  </b>
</a>

Element <c> can appear in any order and there could be a number of <c> with
attribute type="pdf". I want to extract the first occurence of the element <c>
which has a attribute type="pdf". I tried to extract it with
<xsl:value-of select="b/c[attribute::className='pdf'][1]"/>
after matching the template for <a>. But I am getting "First Pdf File Second
Pdf File". Can anyone tell me where I am making mistake. I am using
Saxon-B8.5.
Thanks
Navpreet.