Grandpa Wang has a rectangular vegetable field, 20 meters long and 8 meters wide, one of which is against the wall. If you want to fence this vegetable field, how many meters of fence will you need at least?
王爷爷有一块长方形菜地，长20米，宽8米，其中有一面靠墙．如果要给这块菜地围上篱笆，至少要多少米篱笆？
<gadget id="calculator">8 * 2</gadget>
<output>16</output>

<gadget id="calculator">20 + 16</gadget>
<output>36</output>

<result>36</result>