Cut off a square with a side length of 3 cm from each of the four corners of a square paper, and the remaining parts can fit together into a cube without a cover. What is the surface area of the cube?
在一张正方形纸的四个角处各剪去边长为3厘米的正方形，余下部分正好可以拼成一个无盖正方体，这个正方体的表面积是多少？
<gadget id="calculator">3 ** 2</gadget>
<output>9</output>

<gadget id="calculator">9 * 6</gadget>
<output>54</output>

<gadget id="calculator">54 - 9</gadget>
<output>45</output>

<result>45</result>