How many square decimeters will the surface area be reduced by using 3 cubes with a side length of 1 decimeter to form a cuboid?
用棱长1分米的3个正方体，拼成一个长方体后，表面积减少多少平方分米
<gadget id="calculator">1 * 1 * 4</gadget>
<output>4</output>

<result>4</result>