There are 149 willow trees, poplar trees and pine trees in the park, and there are 2 more poplar trees than pine trees and 7 fewer than willow trees, so how many pine trees are there in the park?
公园里柳树，杨树和松树共149棵，并且杨树比松树多2棵，比柳树少7棵，那么公园里有松树多少棵？
<gadget id="calculator">149 - 2 - 2 - 7</gadget>
<output>138</output>

<gadget id="calculator">138 / 3</gadget>
<output>46</output>

<result>46</result>