There are 52 metasequoia trees on one side of the road. The distance between each adjacent two trees was originally 8 meters, but now the distance between the trees is 12 meters due to the density of the trees. If the tree at the starting point does not move, how many trees do not need to be moved.
公路一边共有水杉树52棵，每相邻两棵之间的距离原来都是8米，现在因树显得较密改成12米的间隔．如果起点的树不动，那么不需要移动的树还有多少棵．
<gadget id="calculator">52 - 1</gadget>
<output>51</output>

<gadget id="calculator">8 * 51</gadget>
<output>408</output>

<gadget id="calculator">2 * 2 * 2 * 3</gadget>
<output>24</output>

<gadget id="calculator">408 / 24</gadget>
<output>17</output>

<result>17</result>