To make a square iron box without a cover whose edge length is 3 decimeters, at least how many iron sheets are needed.
做一个棱长是3分米的无盖正方体铁皮箱，至少需要多少铁皮．
<gadget id="calculator">3 * 3 * 5</gadget>
<output>45</output>

<result>45</result>