The naughty room is 3.5 meters long, 3 meters high and 3 meters wide. Excluding the 4.5 square meters of doors and windows, the walls and roof of the room are covered with wallpaper. How much wallpaper does this room need at least?
淘气的房间长3.5米，高3米，宽3米．除去门窗4.5㎡，房间墙壁和房顶都贴上墙纸，这个房间至少需要多大的墙纸？
<gadget id="calculator">3.5 * 3</gadget>
<output>10.5</output>

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

<gadget id="calculator">18 - 4.5</gadget>
<output>13.5</output>

<gadget id="calculator">10.5 + 18 + 13.5</gadget>
<output>42</output>

<result>42</result>