10
-2 1
2 -2
-1 -2
0 0
2 -1
0 -2
2 2
0 2
-1 -1
1 -2
 40
-8 24
2 -1
1 -18
72 -70
5 -4
-308 436
-19 40
36 -35
-178 265
-1 2
-7 30
-1 0
3 -2
200 -285
17 -16
-35 74
0 -4
-86 106
-1 4
-7 6
0 1
-5 4
-2 3
6 -5
-4 5
181 -262
76 -118
0 0
-7 18
-58 104
-5 6
-6 12
-3 4
1 0
11 -10
-86 130
-3 6
153 -236
-183 270
-33 64
 5
0 -1
0 -2
0 -3
0 -4
0 -5
 10
0 1
-1 -1
1 1
-1 0
1 -1
-2 -1
-2 2
-2 0
0 -2
0 -1
 20
-1 18
-2 5
-5 4
2 -33
9 -18
0 0
11 -22
2 0
-1 2
-4 41
1 6
1 -2
6 -12
0 1
-3 6
3 -6
3 -8
-1 4
2 -5
1 0
 10
2 1
-1 0
-2 -1
-1 1
0 2
2 -2
0 0
-2 -2
0 -2
-2 1
 20
-3 -3
0 4
-3 1
1 1
-1 2
-4 4
3 -1
-3 0
0 2
4 0
2 3
2 4
4 -3
-4 3
-1 1
1 3
-2 4
1 -2
1 -1
3 0
 3
0 0
0 -1
0 1
 10
2 1
-1 1
0 0
-3 1
-2 -3
-1 -2
-1 -1
1 2
3 -2
0 -2
 3
3 3
1 2
1 1
 4
0 0
1 0
2 0
3 0
 9
1 1
1 0
0 1
0 0
-1 0
-1 1
-1 -1
1 -1
0 -1
 7
1 1
-1 -1
1 0
0 1
-1 0
0 -1
0 0

4
 57
 4
 5
 21
 4
 10
 1
 1
 0
 2
 8
 3

#include <bits/stdc++.h>
using namespace std;
int gcd(int a, int b) { return b ? gcd(b, a % b) : a; }
struct line {
  int dx, dy, v;
  line(int ddx, int ddy, int vv) {
    int g = abs(gcd(ddx, ddy));
    if (ddx < 0) ddx = -ddx, ddy = -ddy, vv = -vv;
    if (ddx == 0 && ddy < 0) ddy = -ddy, vv = -vv;
    dx = ddx / g, dy = ddy / g, v = vv / g;
  }
  bool operator<(const line& a) const {
    if (dx != a.dx) return dx < a.dx;
    if (dy != a.dy) return dy < a.dy;
    return v < a.v;
  }
};
const int MAXN = 3100;
int x[MAXN], y[MAXN];
int main() {
  int N;
  scanf("%d", &N);
  for (int i = 0; i < N; i++) scanf("%d%d", &x[i], &y[i]);
  map<line, int> cnt;
  for (int i = 0; i < N; i++)
    for (int j = i + 1; j < N; j++) {
      int dx = x[i] - x[j], dy = y[i] - y[j], c = dx * y[i] - dy * x[i];
      line dl(dx, dy, c);
      ++cnt[dl];
    }
  map<line, int>::iterator iter = cnt.begin();
  int ans = 0;
  while (iter != cnt.end()) {
    if (iter->second >= 3) {
      int vv = iter->second;
      ans += (vv - 1) * (vv - 2) / 2;
    }
    ++iter;
  }
  printf("%d\n", ans);
  return 0;
}
