There are 22 electric poles from A to B. The distance between two adjacent electric poles is 30 meters. To save materials, the distance between two adjacent electric poles is changed to 45 meters. How many The root does not need to be moved.
甲地到乙地共有22根电线杆，相邻两根电线杆的距离都是30米，现为节省材料，把相邻两根电线杆的距离变成每两根相距45米，那么共有多少根不需要移动．
<gadget id="calculator">22 - 1</gadget>
<output>21</output>

<gadget id="calculator">30 * 21</gadget>
<output>630</output>

<gadget id="calculator">630 / 90</gadget>
<output>7</output>

<gadget id="calculator">7 + 1</gadget>
<output>8</output>

<result>8</result>