15 chairs are arranged in a row, the guests come at any time and sit on the empty chairs, and whenever the guests next to him get up and leave at this time, if all the chairs are empty at the beginning, then the chairs How many people can sit at most.
15把椅子排成一排，客人随时来到，并在空椅上就坐，而每当此时与他相邻的客人就起身离去，如果开始时所有椅子都是空着，那么，椅子上最多时坐多少人．
<gadget id="calculator">15 - 1</gadget>
<output>14</output>

<gadget id="calculator">14 / 2</gadget>
<output>7</output>

<gadget id="calculator">7 + 1</gadget>
<output>8</output>

<result>8</result>