There are 10 stations along a certain railway, and the fares are different from station to station, so how many kinds of fares are there?
某铁路沿线共有10个车站，且站与站之间的票价不相同，那么共有多少种票价？
<gadget id="calculator">10 - 1</gadget>
<output>9</output>

<gadget id="calculator">10 * 9</gadget>
<output>90</output>

<result>90</result>