Two people, A and B, compete to climb the stairs. It is known that each floor is the same. When A reaches the 3rd floor, B goes to the 2nd floor. According to this calculation, when A reaches the 9th floor, how many floors does B reach.
甲乙2人比赛爬楼梯，已知每层楼梯相同，当甲到3层时，乙到2层，照这样计算，当甲到9层时，乙到多少层．
<gadget id="calculator">9 - 1</gadget>
<output>8</output>

<gadget id="calculator">3 - 1</gadget>
<output>2</output>

<gadget id="calculator">2 - 1</gadget>
<output>1</output>

<gadget id="calculator">2 / 1</gadget>
<output>2</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">8 * (1/2)</gadget>
<output>4</output>

<gadget id="calculator">4 + 1</gadget>
<output>5</output>

<result>5</result>