To lay a 37-meter-long sewer, use 3-meter and 5-meter-long pipes to complete the laying, and how many pipes are needed at least.
铺设一段37米长的下水道，用3米和5米两种长度的管道铺设完，最少要多少根管道．
<gadget id="calculator">4 + 5</gadget>
<output>9</output>

<result>9</result>