Vanya and Triangles
题目描述
Vanya got bored and he painted n distinct points on the plane. After that he connected all the points pairwise and saw that as a result many triangles were formed with vertices in the painted points. He asks you to count the number of the formed triangles with the non-zero area.
The first line contains integer n (1≤n≤2000) − the number of the points painted on the plane.
Next n lines contain two integers each xi,yi (-100≤xi,yi≤100) − the coordinates of the i-th point. It is guaranteed that no two given points coincide.
In the first line print an integer − the number of triangles with the non-zero area among the painted points.
4
0 0
1 1
2 0
2 2
3
3
0 0
1 1
2 0
1
1
1 1
0
Note to the first sample test. There are 3 triangles formed: (0,0)-(1,1)-(2,0); (0,0)-(2,2)-(2,0); (1,1)-(2,2)-(2,0).
Note to the second sample test. There is 1 triangle formed: (0,0)-(1,1)-(2,0).
Note to the third sample test. A single point doesn't form a single triangle.
题目来源：fps-www.educg.net-codeforce-1-2833.xml.zip；FPS 共享题包，题包内第 1167 题。保留原作者与原赛事署名。