If two cubes with side lengths of 3 cm are put together to form a cuboid, what is the area of the largest of the six sides of the cuboid in square centimeters?
把两个棱长都是3厘米的正方体拼成一个长方体，这个长方体六个面中最大一个面的面积是多少平方厘米．
<gadget id="calculator">6 * 3</gadget>
<output>18</output>

<result>18</result>