If two cubes with edge length 3cm are put together to form a cuboid, how much is the total surface area reduced in cm**2.
棱长是3cm的两个正方体拼成一个长方体，表面积的总和减少了多少cm**2．
<gadget id="calculator">3 * 3 * 2</gadget>
<output>18</output>

<result>18</result>