There is a rectangular iron sheet with a length of 30 cm and a width of 20 cm. After cutting off a square with a side length of 4 cm from the four corners, it is just folded into an iron box without a lid. What is the volume of this iron box in milliliters?
有一块长30厘米、宽20厘米的长方形铁皮，在四个角上分别剪去边长为4厘米的正方形后，正好折成一个无盖铁盒，这个铁盒的容积是多少毫升？
<gadget id="calculator">4 * 2</gadget>
<output>8</output>

<gadget id="calculator">30 - 8</gadget>
<output>22</output>

<gadget id="calculator">20 - 8</gadget>
<output>12</output>

<gadget id="calculator">22 * 12 * 4</gadget>
<output>1_056</output>

<result>1_056</result>