A high-speed train travels between Dazhou and Chengdu and stops at 4 stations throughout the journey. How many different tickets do you need to prepare?
一动车往返于达州和成都之间，全程停靠4个站，共需准备多少种不同的车票．
<gadget id="calculator">1 + 2 + 3</gadget>
<output>6</output>

<gadget id="calculator">6 * 2</gadget>
<output>12</output>

<result>12</result>