The direct train from Qingdao to Shanghai stops at 4 stations. How many different fares are there for this train?
从青岛到上海的直达列车，中途停靠4个站，这次列车共有多少种不同票价．
<gadget id="calculator">5 + 4 + 3 + 2 + 1</gadget>
<output>15</output>

<result>15</result>