circular reservoir has a circumference of 2340 meters. A willow is planted every 9 meters, and a poplar is planted every 3 meters between two adjacent willows. How many trees should be planted in total?
一个圆形水库，周长是2340米，每隔9米种柳树一棵，又在相邻两棵柳树之间每隔3米种杨树一棵，一共要种多少棵树？
<gadget id="calculator">2_340 / 9</gadget>
<output>260</output>

<gadget id="calculator">9 / 3</gadget>
<output>3</output>

<gadget id="calculator">3 - 1</gadget>
<output>2</output>

<gadget id="calculator">2 * 260</gadget>
<output>520</output>

<gadget id="calculator">260 + 520</gadget>
<output>780</output>

<result>780</result>