#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")


#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
typedef long long ll;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define repr(i, n) for (int i = (int)(n) - 1; i >= 0; i--)
#define repk(i, k, n) for (int i = k; i < (int)(n); i++)
#define all(v) v.begin(), v.end()
#define mod1 1000000007
#define mod2 998244353
#define mod3 100000007
#define vi vector<int>
#define vs vector<string>
#define vc vector<char>
#define vl vector<ll>
#define vb vector<bool>
#define vvi vector<vector<int>>
#define vvc vector<vector<char>>
#define vvl vector<vector<ll>>
#define vvb vector<vector<bool>>
#define vvvi vector<vector<vector<int>>>
#define vvvl vector<vector<vector<ll>>>
#define pii pair<int,int>
#define pil pair<int,ll>
#define pli pair<ll, int>
#define pll pair<ll, ll>
#define vpii vector<pair<int,int>>
#define vpll vector<pair<ll,ll>>
#define vvpii vector<vector<pair<int,int>>>
#define vvpll vector<vector<pair<ll,ll>>>

template<typename T> void debug(T e){
    cerr << e << endl;
}

template<typename T> void debug(vector<T> &v){
    rep(i, v.size()){
        cerr << v[i] << " ";
    }
    cerr << endl;
}

template<typename T> void debug(vector<vector<T>> &v){
    rep(i, v.size()){
        rep(j, v[i].size()){
            cerr << v[i][j] << " ";
        }
        cerr << endl;
    }
}

template<typename T> void debug(vector<pair<T, T>> &v){
    rep(i,v.size()){
        cerr << v[i].first << " " << v[i].second << endl;
    }
}

template<typename T> void debug(set<T> &st){
    for (auto itr = st.begin(); itr != st.end(); itr++){
        cerr << *itr << " ";
    }
    cerr << endl;
}

template<typename T> void debug(multiset<T> &ms){
    for (auto itr = ms.begin(); itr != ms.end(); itr++){
        cerr << *itr << " ";
    }
    cerr << endl;
}

template<typename T> void debug(map<T, T> &mp){
    for (auto itr = mp.begin(); itr != mp.end(); itr++){
        cerr << itr->first << " " << itr->second << endl;
    }
}

void debug_out(){
    cerr << endl;
}

template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T){
    cerr << H << " ";
    debug_out(T...);
}

ll my_gcd(ll a, ll b){
    ll ret = 0;
    if (a < b){
        swap(a, b);
    }
    if (b == 0){
        ret = a;
    }
    else{
        ret = my_gcd(b, a % b);
    }
    return ret;
}

int main(){
    ll N;
    cin >> N;
    vl X(N);
    vl Y(N);
    rep(i,N){
        cin >> X[i] >> Y[i];
    }
    vector<bool> pos(N, false);
    for (ll i = 0; i < N; i++){
        vector<pll> vec(N);
        vector<pll> p_vec(N);
        for (ll 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 = dy / abs(dy);
            else if (dy == 0) dx = dx / abs(dx);
            else{
                ll g = my_gcd(abs(dx), abs(dy));
                dx /= g;
                dy /= g;
            }
            vec[j] = pll(dx, dy);
            p_vec[j] = pll(dx, dy);
        }
        sort(all(p_vec));
        //debug(vec);
        for (ll j = 0; j < N; j++){
            if (i == j) continue;
            pll p = pll(vec[j].first * -1, vec[j].second * -1);
            auto itr = lower_bound(all(p_vec), p);
            if (*itr == p){
                pos[j] = true;
            }
        }
    }
    ll ans = 0;
    for (ll i = 0; i < N; i++){
        if (pos[i]) ans++;
    }
    cout << ans << endl;
}