A rectangular flowerbed is 12 meters long and 3 meters wide. One long side of it is against the wall, and the other three sides are surrounded by bamboo fences. How many meters is the bamboo fence?
一个长方形花圃，长12米，宽3米，它的一条长边靠墙，其它三边围上竹篱笆，竹篱笆长多少米．
<gadget id="calculator">3 * 2</gadget>
<output>6</output>

<gadget id="calculator">12 + 6</gadget>
<output>18</output>

<result>18</result>