A rectangular vegetable field is 8 meters long and 5 meters wide, surrounded by a fence. If one side is against a wall, how many meters should the fence be at least?
一块长方形菜地，长是8米，宽是5米，四周围上篱笆，如果一面靠墙，篱笆至少要多少米？
<gadget id="calculator">5 * 2</gadget>
<output>10</output>

<gadget id="calculator">8 + 10</gadget>
<output>18</output>

<result>18</result>