There are still 3 stops on the train between cities A and B, how many types of tickets should be prepared on the train.
往返A、B两个城市的火车还有3个停靠点，则该火车上要准备多少种车票．
<gadget id="calculator">3 + 2</gadget>
<output>5</output>

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

<gadget id="calculator">5 * 4</gadget>
<output>20</output>

<result>20</result>