#include <bits/stdc++.h>
using namespace std;
long long spf[10];
long long fac[10];
void sieve() {
  spf[1] = 1;
  for (long long i = 2; i < 10; i++) spf[i] = i;
  for (long long i = 4; i < 10; i += 2) spf[i] = 2;
  for (long long i = 3; i * i < 10; i++) {
    if (spf[i] == i) {
      for (long long j = i * i; j < 10; j += i)
        if (spf[j] == j) spf[j] = i;
    }
  }
}
map<long long, long long> getfactor(long long a) {
  map<long long, long long> m;
  while (a > 1) {
    m[spf[a]]++;
    a /= spf[a];
  }
  return m;
}
long long power(long long x, long long y, long long p) {
  long long res = 1;
  if (x == 0) return 0;
  while (y > 0) {
    if (y & 1) res = (res * x);
    y = y >> 1;
    x = (x * x);
  }
  return res;
}
long long gcd(long long a, long long b) {
  if (a == 0) return b;
  return gcd(b % a, a);
}
long long inverse(long long a, long long p) { return power(a, p - 2, p); }
long long ncr(long long n, long long r, long long p) {
  if (r == 0) return 1;
  return (fac[n] * inverse(fac[r], p) % p * inverse(fac[n - r], p) % p) % p;
}
long long ret(long long a) { return (a * (a - 1)) / 2; }
void solve() {
  long long n;
  cin >> n;
  set<pair<pair<long double, long double>, long double> > s;
  map<long double, long long> ma;
  pair<long double, long double> p[n];
  for (long long i = 0; i < n; i++) {
    cin >> p[i].first >> p[i].second;
  }
  long double inf = 1e10;
  for (long long i = 0; i < n; i++) {
    for (long long j = i + 1; j < n; j++) {
      long double slope =
          (p[i].second - p[j].second) / (p[i].first - p[j].first);
      if (p[i].first == p[j].first) slope = inf;
      if (s.find(make_pair(p[i], slope)) == s.end() &&
          s.find(make_pair(p[j], slope)) == s.end()) {
        s.insert(make_pair(p[i], slope));
        s.insert(make_pair(p[j], slope));
        ma[slope]++;
      } else {
        if (s.find(make_pair(p[i], slope)) == s.end())
          s.insert(make_pair(p[i], slope));
        else
          s.insert(make_pair(p[j], slope));
      }
    }
  }
  long long sum = 0, tot = 0;
  for (auto it = ma.begin(); it != ma.end(); it++) {
    tot += it->second;
    sum -= ret(it->second);
  }
  sum += ret(tot);
  cout << sum << '\n';
}
signed main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  long long t = 1;
  while (t--) {
    solve();
  }
}
