There is a circular pool in the Civic Center Square with a diameter of 200 meters. Weeping willows are planted every 4 meters along the pool. How many weeping willows should be planted in total?
市民中心广场有一个圆形水池，直径是200米，沿水池一周每隔4米种一棵垂柳，一共要种垂柳多少棵？
<gadget id="calculator">3.14 * 200</gadget>
<output>628</output>

<gadget id="calculator">628 / 4</gadget>
<output>157</output>

<result>157</result>