#include <bits/stdc++.h>
using namespace std;
const long long int INF = 1e18;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int n;
  cin >> n;
  int i, j;
  vector<pair<int, int> > pts;
  for (i = 1; i <= n; i++) {
    int x, y;
    cin >> x >> y;
    pts.push_back(make_pair(x, y));
  }
  vector<pair<double, double> > lines;
  for (i = 0; i < n; i++) {
    for (j = i + 1; j < n; j++) {
      int x1 = pts[i].first;
      int x2 = pts[j].first;
      int y1 = pts[i].second;
      int y2 = pts[j].second;
      double m, c;
      if (x1 == x2) {
        m = 1000000;
        c = x1;
      } else {
        m = ((y2 - y1) * (1.0)) / (x2 - x1);
        c = y1 - m * x1;
      }
      lines.push_back({m, c});
    }
  }
  sort(lines.begin(), lines.end());
  vector<pair<double, double> > lines2;
  lines2.push_back(lines[0]);
  for (i = 1; i < lines.size(); i++) {
    if (lines[i] != lines[i - 1]) {
      lines2.push_back(lines[i]);
    }
  }
  long long ans = 0;
  for (i = 0; i < lines2.size(); i++) {
    for (j = i + 1; j < lines2.size(); j++) {
      if (lines2[i].first != lines2[j].first) ans += 1;
    }
  }
  cout << ans << "\n";
}
