Xiaolan's room is 3.5 meters long, 3 meters wide and 3 meters high. The walls and roof of the room are covered with wallpaper. What is the minimum area of wallpaper needed for this room?
小兰的房间长3.5米，宽和高都是3米．房间的墙壁和房顶都贴上墙纸，这个房间至少需要多大面积的墙纸？
<gadget id="calculator">3.5 * 3</gadget>
<output>10.5</output>

<gadget id="calculator">3.5 * 3 * 2</gadget>
<output>21</output>

<gadget id="calculator">3 * 3 * 2</gadget>
<output>18</output>

<gadget id="calculator">10.5 + 21 + 18</gadget>
<output>49.5</output>

<result>49.5</result>