count the number of descending nodes

hello
i have one xml as this:
<root>
 <no>
  <my>w</my>
  <my>e</my>
 </no>
 <no>
  <my>p</my>
 </no>
</root>

i want to see if above of the no node there is one or more nodes with the
name my.
i make this:
<xsl:for-each select="/root/no">
<xsl:choose>
<xsl:when test="'count(my) =1'">ok</xsl:when>
<xsl:otherwise>no</xsl:otherwise>
</xsl:choose>
</xsl:for-each>

but it doesn't print well.
how can i known if there is one or more nodes child with the mane my?

thanks