An acrobat performs a unicycle tightrope walk. The diameter of the wheel is 50 centimeters. To walk a 31.4-meter-long steel wire, how many times does the wheel need to turn at least?
杂技演员表演独轮车走钢丝，车轮直径为50厘米，要走过长31.4米的钢丝，车轮至少需要转动多少圈？
<gadget id="calculator">50 / 100</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">3.14 * (1/2)</gadget>
<output>1.57</output>

<gadget id="calculator">31.4 / 1.57</gadget>
<output>20</output>

<result>20</result>