#include<algorithm>
#include<array>
#include<bitset>
#include<cmath>
#include<cstdio>
#include<cstring>
#include<iomanip>
#include<iostream>
#include<map>
#include<numeric>
#include<queue>
#include<set>
#include<unordered_map>
#define fi first
#define se second
#define pb push_back
#define mp make_pair
#define endl '\n'
using namespace std;
using ll=long long;
using db=double;
using pii=pair<int,int>;
const int inf=0x3f3f3f3f;
const int mod=998244353;
const db eps=1e-8;
const db PI=acos(-1);
const int N=2e5+10,M=1e3+10;
//?????????????,????????
//???????:?????????(n-2)*PI;?????,??????cos,????-1~1,??acos????
bool sgn(db x){
    return x>eps?1:(x<-eps?-1:0);
}
inline int cmp(db a,db b){return sgn(a-b);}//a=b??0,a>b??1,a<b??-1
struct point{
    db x,y;
    point operator + (const point &a)const{
        return {x+a.x,y+a.y};
    }
    point operator - (const point &a)const{
        return {x-a.x,y-a.y};
    }
    point operator * (const db a)const{
        return {x*a,y*a};
    }
    bool operator<(point p)const{//?????,??????
        int c=cmp(x,p.x);
        if(c)return c==-1;
        return cmp(y,p.y)==-1;
    }
    db abs(){return sqrt(abs2());}
    db abs2(){return x*x+y*y;}
    db distTo(point p){return (*this-p).abs();}
};
double dot(const point &a,const point &b){
    return a.x*b.x+a.y*b.y;
}
double det(const point &a,const point &b){
    return a.x*b.y-a.y*b.x;
}
bool turn_left(const point &a,const point &b,const point &c){
    return sgn(det(b-a,c-a))>0;
}
bool convex_hull(vector<point> a)
{
    sort(a.begin(), a.end()); // ? ? ?: less <pair >
    vector<point> ret;
    for (int i = 0; i < (int)a.size(); i++)
    {
        while (ret.size() > 1 && !turn_left(ret[ret.size() - 2], ret[ret.size() - 1], a[i]))
            return false;
        ret.push_back(a[i]);
    }
    int fixed = (int)ret.size();
    for (int i = (int)a.size() - 2; i >= 0; --i)
    {
        while (ret.size() > fixed && !turn_left(ret[ret.size() - 2], ret[ret.size() - 1], a[i]))
            return false;
        ret.push_back(a[i]);
    }
    ret.pop_back();
    return true;
}

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int n;
    cin >> n;
    vector<point>p(n);
    for(auto &[x,y]:p)
        cin >> x >> y;
    if(convex_hull(p))
    {
        db sum=0;
        for(int i=0;i<n;i++)
        {
            point p1=p[i],p2=p[(i+1)%n],p3=p[(i+2)%n];
            db cost=dot(p2-p1,p2-p3)/p1.distTo(p2)/p2.distTo(p3);
            db theta=acos(cost);
            sum+=theta;
        }
        if(cmp(sum,(n-2)*PI))cout << "No" << endl;
        else cout << "Yes" << endl;
    }
    else cout << "No" << endl;
    return 0;
}