How much fabric is needed to sew a cylindrical pillow with a base radius of 10cm and a length of 50cm? (interface does not count)
缝制一个圆柱形抱枕，底面半径是10cm，长50cm，需要多少布料？(接口处不算)
<gadget id="calculator">2 * 3.14 * 10 * 50</gadget>
<output>3_140</output>

<gadget id="calculator">10 ** 2</gadget>
<output>100</output>

<gadget id="calculator">3.14 * 100 * 2</gadget>
<output>628</output>

<gadget id="calculator">3_140 + 628</gadget>
<output>3_768</output>

<result>3_768</result>