<?xml version="1.0"?>
<docs>
  <d level="1">D1</d>
  <doc2>
    <a level="2">
      <b level="3">3-B2</b>
      <c level="3">3-C3</c>
      <d level="3">D3</d>
    </a>
    <d level="2">D2</d>
  </doc2>
</docs>