Class 3 of Grade 5 in Zhenhai Yale School planted a piece of trees, among which 56 trees were not planted by Class 1, 65 trees were not planted by Class 2, 61 trees were not planted by Class 3, how many trees were planted by Class 2.
镇海雅乐学校5年级3个班种了一片树，其中56棵不是1班种的，65棵不是2班种的，61棵不是3班种的，2班种了多少棵．
<gadget id="calculator">61 - 65</gadget>
<output>-4</output>

<gadget id="calculator">56 + (-4)</gadget>
<output>52</output>

<gadget id="calculator">52 / 2</gadget>
<output>26</output>

<result>26</result>