Xiaolan's room is 3.5 meters long, 4 meters wide, and 3 meters high. Excluding the 4.5m**2 of doors and windows, 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4米，高3米．除去门窗4.5米**2，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 * 4</gadget>
<output>14</output>

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

<gadget id="calculator">3 * 4 * 2</gadget>
<output>24</output>

<gadget id="calculator">24 - 4.5</gadget>
<output>19.5</output>

<gadget id="calculator">14 + 21 + 19.5</gadget>
<output>54.5</output>

<result>54.5</result>