train travels from A to B, and there are 4 stops in the middle, so how many fares should be prepared along the way for this train to go from A to B?
一列火车从甲地开往乙地，中间要停靠4个站，那么这列火车在从甲地开往乙地的过程中，沿途一共要准备多少种票价．
<gadget id="calculator">5 + 4 + 3 + 2 + 1</gadget>
<output>15</output>

<result>15</result>