A sheep is tied by a rope 20 meters long, what is the maximum area that the sheep can graze on?
一只羊被一根20米长的绳子拴住，这只羊吃草的最大面积是多少？
<gadget id="calculator">20 ** 2</gadget>
<output>400</output>

<gadget id="calculator">3.14 * 400</gadget>
<output>1_256</output>

<result>1_256</result>