cuboid biscuit box is 20cm long, 8cm wide, and 15cm high. If a circle of trademark paper is pasted around it (not on the top and bottom), what is the area of this trademark paper in square centimeters?
一个长方体的饼干盒，长20cm，宽8cm，高15cm．如果围着它贴一圈商标纸(上下面不贴)，这张商标纸的面积是多少平方厘米？
<gadget id="calculator">20 * 15</gadget>
<output>300</output>

<gadget id="calculator">8 * 15</gadget>
<output>120</output>

<gadget id="calculator">300 + 120</gadget>
<output>420</output>

<gadget id="calculator">420 * 2</gadget>
<output>840</output>

<result>840</result>