#include <bits/stdc++.h>
#define x first
#define y second
using namespace std;
const int N = 1e5+10;
typedef pair<double,double> PDD;
vector<PDD> alls;
int n;
bool used[N];
PDD operator-(PDD a,PDD b){
    return {a.x-b.x,a.y-b.y};
}

double cross(PDD a,PDD b){ 
    return a.x*b.y-b.x*a.y;
}

double area(PDD a,PDD b,PDD c){
    return cross(b-a,c-a);
}

int main(){
    cin>>n;
    for(int i = 1;i<=n;i++){
        double x,y;
        cin>>x>>y;
        alls.push_back({x,y});
    }
    sort(alls.begin(),alls.end());
    int stk[N];
    int tt = 0;
    for(int i = 0;i<n;i++){
        while(tt>=2&&area(alls[stk[tt-1]],alls[stk[tt]],alls[i])>=0)used[stk[tt--]] = false;
        stk[++tt] = i;
        used[i] = true;
    }
    used[0] = false;
    for(int i = n-1;i>=0;i--){
        if(used[i]) continue;
        while(tt>=2&&area(alls[stk[tt-1]],alls[stk[tt]],alls[i])>=0)tt--;
        stk[++tt] = i;
    }


}