There are 61 telephone poles on one side of a road. Originally, the distance between every two electric poles was 50 meters, but now it is changed to 60 meters. How many utility poles do not need to be moved except the two at both ends?
一条公路的一边有61根电线杆．原来每两根电线杆之间的距离是50米，现在改为60米．除两端的两根不需移动外，还有多少根电线杆不用移动？
<gadget id="calculator">61 - 1</gadget>
<output>60</output>

<gadget id="calculator">50 * 60</gadget>
<output>3_000</output>

<gadget id="calculator">3_000 / 300</gadget>
<output>10</output>

<gadget id="calculator">10 - 1</gadget>
<output>9</output>

<result>9</result>