#include <bits/stdc++.h>
using namespace std;
using ll=long long;
const ll ILL=2167167167167167167;
const int INF=2100000000;
#define rep(i,a,b) for (int i=(int)(a);i<(int)(b);i++)
#define all(p) p.begin(),p.end()
template<class T> using _pq = priority_queue<T, vector<T>, greater<T>>;
template<class T> int LB(vector<T> &v,T a){return lower_bound(v.begin(),v.end(),a)-v.begin();}
template<class T> int UB(vector<T> &v,T a){return upper_bound(v.begin(),v.end(),a)-v.begin();}
template<class T> bool chmin(T &a,T b){if(b<a){a=b;return 1;}else return 0;}
template<class T> bool chmax(T &a,T b){if(a<b){a=b;return 1;}else return 0;}
template<class T> void So(vector<T> &v) {sort(v.begin(),v.end());}
template<class T> void Sore(vector<T> &v) {sort(v.begin(),v.end(),[](T x,T y){return x>y;});}
bool yneos(bool a,bool upp=false){if(a){cout<<(upp?"YES\n":"Yes\n");}else{cout<<(upp?"NO\n":"No\n");}return a;}
template<class T> void vec_out(vector<T> &p,int ty=0){
    if(ty==2){cout<<'{';for(int i=0;i<(int)p.size();i++){if(i){cout<<",";}cout<<'"'<<p[i]<<'"';}cout<<"}\n";}
    else{if(ty==1){cout<<p.size()<<"\n";}for(int i=0;i<(int)(p.size());i++){if(i) cout<<" ";cout<<p[i];}cout<<"\n";}}
template<class T> T vec_min(vector<T> &a){assert(!a.empty());T ans=a[0];for(auto &x:a) chmin(ans,x);return ans;}
template<class T> T vec_max(vector<T> &a){assert(!a.empty());T ans=a[0];for(auto &x:a) chmax(ans,x);return ans;}
template<class T> T vec_sum(vector<T> &a){T ans=T(0);for(auto &x:a) ans+=x;return ans;}
int pop_count(long long a){int res=0;while(a){res+=(a&1),a>>=1;}return res;}
template<class T> T square(T a){return a * a;}

std::vector<std::pair<long long,long long>> convex_hull(std::vector<std::pair<long long,long long>> P){
    /*
    Copyright (c) 2021 0214sh7
    https://github.com/0214sh7/library/
    */
    if(P.size()<=2){
        return P;
    }
    std::vector<std::pair<long long,long long>> H,L,R;
    sort(P.begin(),P.end());

    //下半分
    for(int i=0;i<(int)P.size();i++){
        int j=L.size();
        while(j>=2 && (L[j-1].first-L[j-2].first)*(P[i].second-L[j-2].second)<=(L[j-1].second-L[j-2].second)*(P[i].first-L[j-2].first)){
            L.pop_back();
            j--;
        }
        L.push_back(P[i]);
    }

    //上半分
    for(int i=(int)P.size()-1;i>=0;i--){
        int j=H.size();
        while(j>=2 && (H[j-1].first-H[j-2].first)*(P[i].second-H[j-2].second)<=(H[j-1].second-H[j-2].second)*(P[i].first-H[j-2].first)){
            H.pop_back();
            j--;
        }
        H.push_back(P[i]);
    }


    R=L;
    for(int i=1;i<H.size()-1;i++){
        R.push_back(H[i]);
    }

    return R;
}

void solve();
// CITRUS CURIO CITY / FREDERIC
int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int t = 1;
    // cin >> t;
    rep(i, 0, t) solve();
}

void solve(){
    int N;
    cin >> N;
    vector<pair<ll, ll>> p(N);
    rep(i, 0, N) cin >> p[i].first >> p[i].second;
    auto ans = convex_hull(p);
    yneos((int)(ans.size()) == N);
}