A set of books is divided into volumes one and two, each of which measures 20 cm, 15 cm, and 8 cm in length, width, and height. What is the minimum square centimeter of wrapping paper used to pack this set of books?
一套书分为上、下册，每本长宽高分别为20厘米15厘米8厘米．包装这套书至少用多少平方厘米的包装纸？
<gadget id="calculator">20 * 15</gadget>
<output>300</output>

<gadget id="calculator">8 * 2</gadget>
<output>16</output>

<gadget id="calculator">20 * 16</gadget>
<output>320</output>

<gadget id="calculator">15 * 16</gadget>
<output>240</output>

<gadget id="calculator">300 + 320 + 240</gadget>
<output>860</output>

<gadget id="calculator">860 * 2</gadget>
<output>1_720</output>

<result>1_720</result>