Uncle Wang surrounded a rectangular vegetable garden with a fence against one wall. The length of the vegetable garden is 12 meters and the width is 8 meters. How many meters should the fence be at least?
王大爷用篱笆靠一面墙围一个长方形菜园，菜园的长是12米，宽是8米，最少要用篱笆多少米．
<gadget id="calculator">8 * 2</gadget>
<output>16</output>

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

<result>28</result>