The perimeter of the volleyball court is 54 meters and the width is 9 meters. What is the length of the volleyball court in meters?
排球场的周长是54米，宽是9米，排球场的长是多少米？
<gadget id="calculator">54 / 2</gadget>
<output>27</output>

<gadget id="calculator">27 - 9</gadget>
<output>18</output>

<result>18</result>