<NQueens id="1">
  <id>0</id>
  <n>4</n>
  <columnList id="2">
    <Column id="3">
      <id>0</id>
      <index>0</index>
    </Column>
    <Column id="4">
      <id>1</id>
      <index>1</index>
    </Column>
    <Column id="5">
      <id>2</id>
      <index>2</index>
    </Column>
    <Column id="6">
      <id>3</id>
      <index>3</index>
    </Column>
  </columnList>
  <rowList id="7">
    <Row id="8">
      <id>0</id>
      <index>0</index>
    </Row>
    <Row id="9">
      <id>1</id>
      <index>1</index>
    </Row>
    <Row id="10">
      <id>2</id>
      <index>2</index>
    </Row>
    <Row id="11">
      <id>3</id>
      <index>3</index>
    </Row>
  </rowList>
  <queenList id="12">
    <Queen id="13">
      <id>0</id>
      <column reference="3"/>
    </Queen>
    <Queen id="14">
      <id>1</id>
      <column reference="4"/>
    </Queen>
    <Queen id="15">
      <id>2</id>
      <column reference="5"/>
    </Queen>
    <Queen id="16">
      <id>3</id>
      <column reference="6"/>
    </Queen>
  </queenList>
</NQueens>