The diameter of a circular fountain is 20 meters, and a railing is placed 1 meter away from the edge of the pool. How many meters is the railing?
一个圆形喷水池的直径是20米，在离水池边1米的地方围上一圈栏杆，栏杆的长多少米？
<gadget id="calculator">20 + 1 + 1</gadget>
<output>22</output>

<gadget id="calculator">3.14 * 22</gadget>
<output>69.08</output>

<result>69.08</result>