#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using P = pair<ll,ll>;
#define fix(x) fixed << setprecision(x)
#define asc(x) x, vector<x>, greater<x>
#define rep(i, n) for(ll i = 0; i < n; i++)
#define all(x) (x).begin(),(x).end()
template<class T>bool chmin(T&a, const T&b){if(a>b){a=b;return 1;}return 0;}
template<class T>bool chmax(T&a, const T&b){if(a<b){a=b;return 1;}return 0;}
constexpr ll INFLL = (1LL << 62), MOD = 998244353;
constexpr int INF = (1 << 30);

int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    int n;
    cin >> n;
    vector<ll> x(n), y(n);
    rep(i,n) cin >> x[i] >> y[i];
    int ans = 0;
    rep(i,n){
        set<pair<ll,ll>> se;
        rep(j,n){
            if(j==i) continue;
            ll p = x[j]-x[i], q = y[j]-y[i], g = abs(__gcd(p,q));
            p /= g, q /= g;
            if(se.count({p,q})){
                ans++;
                break;
            }
            se.insert({p,q});
        }
    }
    cout << ans << '\n';
    return 0;
}