box with a length of 20 centimeters, a width of 15 centimeters, and a height of 30 centimeters is now to be pasted with label paper around it. How many square centimeters of label paper is needed?
一个长20厘米，宽15厘米，高30厘米的盒子，现在要在它的四周贴上商标纸，需要多少平方厘米的商标纸？
<gadget id="calculator">20 * 30</gadget>
<output>600</output>

<gadget id="calculator">15 * 30</gadget>
<output>450</output>

<gadget id="calculator">600 + 450</gadget>
<output>1_050</output>

<gadget id="calculator">1_050 * 2</gadget>
<output>2_100</output>

<result>2_100</result>