There is a bus with 12 stops including the starting point and the ending point. If a car except the terminal, among the passengers who get on the bus at each stop, exactly one passenger will get off at each stop after this stop. Q: How many passengers are there at most in the bus?
有一路公共汽车，包括起点和终点共有12个车站．如果一辆车除终点外，每一站上车的乘客中，恰好各有一位乘客到这一站以后的每一站下车．问：公共汽车内最多时有多少位乘客？
<gadget id="calculator">12 - 1</gadget>
<output>11</output>

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

<gadget id="calculator">9 - 2</gadget>
<output>7</output>

<gadget id="calculator">8 - 3</gadget>
<output>5</output>

<gadget id="calculator">7 - 4</gadget>
<output>3</output>

<gadget id="calculator">6 - 5</gadget>
<output>1</output>

<gadget id="calculator">11 + 9 + 7 + 5 + 3 + 1</gadget>
<output>36</output>

<result>36</result>