A living room is 8 meters long, 6 meters wide, and 3.5 meters high. It is necessary to use wallpaper to decorate its surrounding walls. It is known that the area of doors and windows is 12 square meters. How much wallpaper should I buy at least?
一间会客厅长8米，宽6米，高3.5米，要用壁纸装修它的四周墙壁，已知门窗面积是12平方米，问至少要买多少壁纸？
<gadget id="calculator">8 * 3.5</gadget>
<output>28</output>

<gadget id="calculator">6 * 3.5</gadget>
<output>21</output>

<gadget id="calculator">28 + 21</gadget>
<output>49</output>

<gadget id="calculator">49 * 2</gadget>
<output>98</output>

<gadget id="calculator">98 - 12</gadget>
<output>86</output>

<result>86</result>