#include <bits/stdc++.h>   using namespace std;   int main() {     ios_base::sync_with_stdio(false);     cin.tie(NULL);     long long n;     cin >> n;     vector<pair<long long, long long> > p;     for (long long i = 0; i < n; i++) {       double x, y;       cin >> x >> y;       p.push_back(make_pair(x, y));     }     set<pair<double, double> > s;     set<double> e;     long long c;     for (long long i = 0; i < n; i++) {       for (long long j = i + 1; j < n; j++) {         double x1 = p[i].first;         double y1 = p[i].second;         double x2 = p[j].first;         double y2 = p[j].second;         if ((x2 - x1) != 0) {           double m = (y2 - y1) / (x2 - x1);           double c = y1 - m * (x1);           s.insert(make_pair(m, c));         } else {           e.insert(x1);         }       }     }     set<pair<double, double> >::iterator it;     vector<long long> r;     long long k = 0;     long long w = 0;     set<pair<double, double> >::iterator itr;     itr = s.begin();     it = s.begin();     it++;     while (it != s.end()) {       long long u = 0;       pair<double, double> gg = *it;       pair<double, double> hh = *itr;       while (gg.first == hh.first) {         u++;         it++;         itr++;         gg = *it;         hh = *itr;       }       if (u != 0) {         w = w + ((u + 1) * u) / 2;       }       it++;       itr++;     }     c = e.size();     long long total = s.size() + c;     total = (total * (total - 1)) / 2;     w = w + ((c - 1) * c) / 2;     cout << (total - w);     return 0;   }   