If there are 5 trees planted on each side of a hexagonal pond, how many trees should be planted at least?
在一个六边形的池塘边种树，每边都种5棵树，最少要种多少棵？
<gadget id="calculator">5 * 6</gadget>
<output>30</output>

<gadget id="calculator">30 - 6</gadget>
<output>24</output>

<result>24</result>