On one side of a straight runway, 8 red flags (both ends) are inserted equidistantly, how many sections are the runway divided into.
在一条笔直跑道的一边等距离地插了8面红旗(两端都插)，把这条跑道分成了多少段．
<gadget id="calculator">8 - 1</gadget>
<output>7</output>

<result>7</result>