There is a rectangular flower bed. Its length is 13 meters and its width is 9 meters. What is the perimeter of this flower bed in meters?
有一个长方形花坛，量得它的长是13米，宽是9米，这个花坛的周长是多少米．
<gadget id="calculator">13 + 9</gadget>
<output>22</output>

<gadget id="calculator">22 * 2</gadget>
<output>44</output>

<result>44</result>