CF552D.Vanya and Triangles

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.

万尼亚感到无聊，于是在平面上画了 n 个互不相同的点。之后，他将所有点两两相连，发现由此形成了许多以所画点为顶点的三角形。他请你计算所形成的所有面积不为零的三角形的个数。

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 x__i, y__i ( - 100 ≤ x__i, y__i ≤ 100) — the coordinates of the i-th point. It is guaranteed that no two given points coincide.

第一行包含一个整数 $n$（$1 \leq n \leq 2000$）—— 表示平面上被涂色的点的数量。

接下来的 $n$ 行，每行包含两个整数 $x_i$、$y_i$（$-100 \leq x_i, y_i \leq 100$）—— 表示第 $i$ 个点的坐标。保证任意两个给定的点均不重合。

In the first line print an integer — the number of triangles with the non-zero area among the painted points.

第一行输出一个整数——所有被涂色的点中能构成面积不为零的三角形的个数。

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.

第一个样例测试说明：共形成 3 个三角形：$(0,\,0)\,-\,(1,\,1)\,-\,(2,\,0)$；$(0,\,0)\,-\,(2,\,2)\,-\,(2,\,0)$；$(1,\,1)\,-\,(2,\,2)\,-\,(2,\,0)$。

第二个样例测试说明：共形成 1 个三角形：$(0,\,0)\,-\,(1,\,1)\,-\,(2,\,0)$。

第三个样例测试说明：单个点无法构成三角形。