A total of 48 willow trees are planted on one side of the road, and a poplar tree is planted between every two willow trees. How many poplar trees are there in total?
马路一边共栽了48棵柳树，每两棵柳树之间栽一棵杨树，共有多少棵杨树．
<gadget id="calculator">48 - 1</gadget>
<output>47</output>

<result>47</result>