certain express train from A to B has to stop at 3 major stations. How many different fares should the railway bureau set for this express train?
从甲地到乙地的某次快车中途要停靠3个大站，铁路局要为这次快车制定多少种不同的票价．
<gadget id="calculator">4 + 3 + 2 + 1</gadget>
<output>10</output>

<result>10</result>