To place flower pots on the edge of the pentagonal pool so that there are 5 pots of flowers on each side, how many pots of flowers are needed at least?
要在五边形的水池边上摆上花盆，使每一边都有5盆花，最少需要几盆花？
<gadget id="calculator">5 - 1</gadget>
<output>4</output>

<gadget id="calculator">4 * 5</gadget>
<output>20</output>

<result>20</result>