An acrobatic troupe has a unicycle performance. The diameter of the wheel is 40 cm. To walk a 31.4-meter-long wire rope, how many weeks does the wheel need to roll?
某杂技团有一种独轮车表演，车轮直径是40厘米，要走完31.4米长的钢丝绳，车轮需滚动几周？
<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">3.14 * (2/5)</gadget>
<output>1.256</output>

<gadget id="calculator">31.4 / 1.256</gadget>
<output>25</output>

<result>25</result>