From A to B, one utility pole was installed every 45 meters, and there are 65 utility poles including the two at both ends. Now it is changed to install one utility pole every 60 meters, except for the two at both ends. In addition to the need to move, how many roots do not need to be moved in the middle?
从甲地到乙地原来每隔45米要安装1根电线杆，加上两端的2根一共有65根电线杆，现在改成每隔60米安装1根电线杆，除两端2根不需移动外，中途还有多少根不必移动？
<gadget id="calculator">65 - 1</gadget>
<output>64</output>

<gadget id="calculator">2 * 2 * 3 * 3 * 5</gadget>
<output>180</output>

<gadget id="calculator">64 / 180</gadget>
<output>16/45 = around 0.355556</output>

<gadget id="calculator">45 * (16/45)</gadget>
<output>16</output>

<gadget id="calculator">16 - 1</gadget>
<output>15</output>

<result>15</result>