#ifdef LOCAL
#include <local.hpp>
#else
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2,popcnt,lzcnt,abm,bmi,bmi2")
#include <bits/stdc++.h>
#define debug(...) ((void)0)
#define postprocess(...) ((void)0)
#endif

using namespace std;
using ll = long long;
using ld = long double;

void solve([[maybe_unused]] int test) {
    int N;
    cin >> N;

    ll X[N], Y[N];
    for (int i = 0; i < N; i++) {
        cin >> X[i] >> Y[i];
    }

    ll ans = 0;

    for (int i = 0; i < N; i++) {
        map<pair<ll, ll>, int> cnt;

        for (int j = 0; j < N; j++) {
            if (i == j) continue;

            ll dX = X[j] - X[i];
            ll dY = Y[j] - Y[i];

            if (dX != 0 && dY != 0) {
                ll div = gcd(abs(dX), abs(dY));
                dX /= div;
                dY /= div;
            } else {
                dX = (dX ? dX / abs(dX) : 0);
                dY = (dY ? dY / abs(dY) : 0);
            }

            cnt[{dX, dY}]++;
        }

        bool bad = false;
        for (auto&& [_, num] : cnt) {
            if (num > 1) bad = true;
        }
        if (bad) ans++;
    }

    cout << ans << endl;
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int t = 1;
    // cin >> t;
    for (int i = 1; i <= t; i++) {
        solve(i);
    }

    postprocess();
}