rectangular flowerbed is 12 meters long and 8 meters wide. One side of it is against the wall, and the other three sides are surrounded by fences. How many meters is the minimum required for the fence?
一块长方形的花圃，长12米，宽8米，它的一条边靠墙，其余三边围上篱笆，篱笆至少需要多少米？
<gadget id="calculator">8 * 2</gadget>
<output>16</output>

<gadget id="calculator">12 + 16</gadget>
<output>28</output>

<result>28</result>