A train from Huainan to Beijing needs to stop at 6 stations in addition to the starting point and the ending point. How many different tickets should be prepared in total?
淮南到北京之间开行一列火车，除起点和终点外，还要停靠6个站，一共要准备多少种不同的车票．
<gadget id="calculator">7 + 6 + 5 + 4 + 3 + 2 + 1</gadget>
<output>28</output>

<gadget id="calculator">28 * 2</gadget>
<output>56</output>

<result>56</result>