An acrobat performs a unicycle tightrope walk. The diameter of the wheel is 0.5 meters. To walk a 21.98-meter-long steel wire, how many turns does the wheel have to make?
杂技演员表演独轮车走钢丝，车轮的直径是0.5米，要走过21.98米长的钢丝，车轮要转多少圈？
<gadget id="calculator">3.14 * 0.5</gadget>
<output>1.57</output>

<gadget id="calculator">21.98 / 1.57</gadget>
<output>14</output>

<result>14</result>