Two electric poles are 200 meters apart, and a tree is planted every 5 meters between the two electric poles. How many trees can be planted in total?
两根电杆相距200米，在两电杆之间每隔5米种一棵树，一共可以种多少棵树．
<gadget id="calculator">200 / 5</gadget>
<output>40</output>

<gadget id="calculator">40 - 1</gadget>
<output>39</output>

<result>39</result>