There is a garden in front of the window of Xiaohong's house, which is 9 meters long and 6 meters longer than the width. Xiaohong wants to use iron fences to surround the garden, one side against the wall, at least how many iron fences should be prepared?
小红家窗前有一个花园，长9米，比宽长6米．小红想用铁栅栏把花园围起来，一面靠墙，至少要准备多少铁栅栏？
<gadget id="calculator">9 - 6</gadget>
<output>3</output>

<gadget id="calculator">3 * 2</gadget>
<output>6</output>

<gadget id="calculator">9 + 6</gadget>
<output>15</output>

<result>15</result>