If two cubes with side lengths of 3 cm are put together to form a cuboid, the surface area of the two cubes is reduced by the sum of the surface areas of the original two cubes by how many square centimeters.
两个棱长为3厘米的正方体拼成一个长方体，表面积比原来的两个正方体的表面积和减少了多少平方厘米．
<gadget id="calculator">3 * 3 * 2</gadget>
<output>18</output>

<result>18</result>