There are 25 telephone poles in a row on the highway. The distance between the two poles was originally 45 meters, but now it is changed to 60 meters. How many poles do not need to be moved?
公路上一排电线杆，共25根，原来两根之间的距离45米，现在要改成60米，有多少根不用动．
<result>7</result>