A rectangular vegetable field is 20 meters long and 8 meters wide. One side is against a wall, and the other three sides are surrounded by fences. How long is the fence at least?
一块长方形菜地，长20米，宽8米，其中一面靠墙，其他三面围上栅栏，栅栏至少长多少米？
<gadget id="calculator">8 * 2</gadget>
<output>16</output>

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

<result>36</result>