There are 7 points on the plane, any three of which are not on the same straight line, if 17 line segments are connected between these 7 points. So how many triangles can these line segments form?
在平面上有7个点，其中任意三个点都不在同一条直线上，如果在这7个点之间连接17条线段．那么这些线段最多能构成多少个三角形？
<gadget id="calculator">35 - 5 - 4 - 3 - 2</gadget>
<output>21</output>

<result>21</result>