A rectangular vegetable field with a length of 16 meters and a width of 12 meters is surrounded by a fence along one wall. What is the minimum length of the fence?
沿着一面墙用篱笆围一个长16米，宽12米的长方形菜地，最少需要准备多长的篱笆？
<gadget id="calculator">16 + 12</gadget>
<output>28</output>

<gadget id="calculator">28 * 2</gadget>
<output>56</output>

<gadget id="calculator">56 - 16</gadget>
<output>40</output>

<result>40</result>