#include<bits/stdc++.h>
using namespace std;
//#pragma GCC optimize("Ofast")

#define rep(i,n) for(ll i=0;i<n;i++)
#define repl(i,l,r) for(ll i=(l);i<(r);i++)
#define per(i,n) for(ll i=(n)-1;i>=0;i--)
#define perl(i,r,l) for(ll i=r-1;i>=l;i--)
#define fi first
#define se second
#define pb push_back
#define ins insert
#define pqueue(x) priority_queue<x,vector<x>,greater<x>>
#define all(x) (x).begin(),(x).end()
#define CST(x) cout<<fixed<<setprecision(x)
#define vtpl(x,y,z) vector<tuple<x,y,z>>
#define rev(x) reverse(x);
using ll=long long;
using vl=vector<ll>;
using vvl=vector<vector<ll>>;
using pl=pair<ll,ll>;
using vpl=vector<pl>;
using vvpl=vector<vpl>;
const ll MOD=1000000007;
const ll MOD9=998244353;
const int inf=1e9+10;
const ll INF=4e18;
const ll dy[9]={1,0,-1,0,1,1,-1,-1,0};
const ll dx[9]={0,1,0,-1,1,-1,1,-1,0};
template<class T> inline bool chmin(T& a, T b) {
    if (a > b) {
        a = b;
        return true;
    }
    return false;
}
template<class T> inline bool chmax(T& a, T b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}


int main(){
    ll n;cin >> n;
    vl x(n),y(n);
    rep(i,n)cin >> x[i] >> y[i];
    vl ans(n);
    rep(i,n){
        rep(j,i){
            rep(k,j){
                double a=x[i]-x[j];a*=y[i]-y[k];
                double b=x[i]-x[k];b*=y[i]-y[j];
                if(a==b){
                    //cout << i <<" " << j <<" " << k << endl;
                    if(x[i]==x[j]){
                        if(y[i]>max(y[j],y[k])||y[i]<min(y[j],y[k]))ans[i]++;
                        if(y[j]>max(y[i],y[k])||y[j]<min(y[i],y[k]))ans[j]++;
                        if(y[k]>max(y[i],y[j])||y[k]<min(y[i],y[j]))ans[k]++;
                    }
                    else{
                        if(x[i]>max(x[j],x[k])||x[i]<min(x[j],x[k]))ans[i]++;
                        if(x[j]>max(x[i],x[k])||x[j]<min(x[i],x[k]))ans[j]++;
                        if(x[k]>max(x[i],x[j])||x[k]<min(x[i],x[j]))ans[k]++;
                    }
                }
            }
        }
    }
    ll ret=0;
    rep(i,n)if(ans[i])ret++;
    cout << ret << endl;
}