The distance between the Elephant House and Monkey Mountain is 60m. The greening team will plant trees on both sides of the path between the two pavilions (not at both ends), and the distance between two adjacent trees is 3m. How many trees will be planted in total.
大象馆和猴山相距60m．绿化队要在两馆间的小路两旁栽树(两端不栽)，相邻两棵树之间的距离是3m．一共要栽多少棵树．
<gadget id="calculator">60 / 3</gadget>
<output>20</output>

<gadget id="calculator">20 - 1</gadget>
<output>19</output>

<gadget id="calculator">19 * 2</gadget>
<output>38</output>

<result>38</result>