#include <bits/stdc++.h>
using namespace std;
#include <atcoder/all>
using namespace atcoder;
using ll = long long;
using ld = long double;
using P = pair<int, int>;
using Graph = vector<vector<ll>>;
using vi = vector<int>;
using vl = vector<long>;
using vll = vector<long long>;
using vvi = vector<vi>;
using vvl = vector<vl>;
using vvll = vector<vll>;
using vs = vector<string>;
using vc = vector<char>;
using vvc = vector<vc>;
using pll = pair<long long, long long>;
using vpll = vector<pll>;
using mint = modint1000000007;
const long long INF = 1e18;
#define reps(i, a, n) for (ll i = (a); i < (ll)(n); i++)
#define rep(i, n) for (ll i = (0); i < (ll)(n); i++)
#define rrep(i, n) for (ll i = (1); i < (ll)(n + 1); i++)
#define repd(i, n) for (ll i = n - 1; i >= 0; i--)
#define rrepd(i, n) for (ll i = n; i >= 1; i--)
#define ALL(n) begin(n), end(n)
#define IN(a, x, b) (a <= x && x < b)
#define INIT                          \
    std::ios::sync_with_stdio(false); \
    std::cin.tie(0);
template <class T>
inline T CHMAX(T &a, const T b) {
    return a = (a < b) ? b : a;
}
template <class T>
inline T CHMIN(T &a, const T b) {
    return a = (a > b) ? b : a;
}
#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
array<ll, 1510> X;
array<ll, 1510> Y;
int main() {
    INIT;
    ll N;
    cin >> N;

    rrep(i, N) { cin >> X[i] >> Y[i]; }
    set<ll> se;
    rrep(i, N) {
        set<pll> ma;
        rrep(j, N) {
            if (i != j) {
                pll ve = {X[j] - X[i], Y[j] - Y[i]};
                ll g = gcd(ve.first, ve.second);
                ve.first /= g;
                ve.second /= g;
                ma.insert(ve);
            }
        }
        rrep(j, N) {
            if (i != j) {
                pll ve = {X[j] - X[i], Y[j] - Y[i]};
                ll g = gcd(ve.first, ve.second);
                ve.first /= g;
                ve.second /= g;
                if (ma.count({-ve.first, -ve.second})) {
                    se.insert(j);
                }
            }
        }
    }
    cout << se.size() << endl;
}