Xiaoqiang's bed is 18 decimeters long and 15 decimeters wide. What is the perimeter of the bed?
小强的床长18分米，宽15分米，床面的周长是多少分米？
<gadget id="calculator">18 + 15</gadget>
<output>33</output>

<gadget id="calculator">33 * 2</gadget>
<output>66</output>

<result>66</result>