A bus runs from the starting station to the terminal station, and there are 13 stops on the way. If the bus leaves from the starting station, except for the terminal station, among the passengers who get on the bus at each station There is exactly one passenger getting on and off at each station. In order for each passenger to have a seat, the car should have at least as many seats as possible.
某公共汽车从起点站开往终点站，中途共有13个停车站，如果这辆公共汽车从起点站开出，除终点站外，每一站上车的乘客中从这一站到以后的每一站正好各有一位乘客上下车，为了使每位乘客都有座位，那么这辆汽车至少应有座位多少个．
<gadget id="calculator">6 * 7</gadget>
<output>42</output>

<result>42</result>