Cut 3 round iron sheets with a radius of 1 cm, at least a rectangular iron sheet with a perimeter of how many centimeters.
剪3个半径为1厘米的圆铁片，至少要准备周长为多少厘米的长方形铁片．
<gadget id="calculator">2 * 1 * 3</gadget>
<output>6</output>

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

<gadget id="calculator">6 + 2</gadget>
<output>8</output>

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

<result>16</result>