The school needs to paint the ceiling and walls of the conference room. The conference room is 20 meters long, 12 meters wide, and 3 meters high. The area of doors and windows is 35 square meters. How many square meters does it need to paint?
学校要粉刷会议室的顶棚和四壁，会议室长20米，宽12米，高3米，扣除门窗面积35平方米，需要粉刷的面积有多少平方米？
<gadget id="calculator">20 * 12</gadget>
<output>240</output>

<gadget id="calculator">20 + 12</gadget>
<output>32</output>

<gadget id="calculator">32 * 2 * 3</gadget>
<output>192</output>

<gadget id="calculator">192 - 35</gadget>
<output>157</output>

<gadget id="calculator">240 + 157</gadget>
<output>397</output>

<result>397</result>