A cuboid carton without upper and lower bottoms, if cut along the height, is a square with a side length of 3 cm. What is the surface area of the original cuboid box in square centimetres?
一个长方体形的无上、下底面的纸盒，若沿着高剪开后是一个边长为3厘米的正方形．那么原来长方体纸盒的表面积是多少平方厘米．
<gadget id="calculator">3 * 3</gadget>
<output>9</output>

<result>9</result>