#include <bits/stdc++.h>
using namespace std;
//premBhai
#define inc(i,n) for(int i=0;i<n;i++)
#define dec(i,n) for(int i=n-1;i>-1;i--)
#define ll long long int
#define mod 1000000007
#define in(n) cin>>n
#define in2(a,b) cin>>a>>b
#define in3(a,b,c) cin>>a>>b>>c
#define pr(x) cout<<x<<'\n'
#define pr2(x,y) cout<<x<<" "<<y<<'\n'
#define pr3(x,y,z) cout<<x<<" "<<y<<" "<<z<<'\n'
#define fill(a,n,x) for(int i=0;i<n;i++) a[i]=x;
#define printArr(a,n) for(int i=0;i<n;i++) cout<<a[i]<<" ";
#define inArr(a,n) for(int i=0;i<n ;i++) cin>>a[i];
#define mp make_pair
#define sz(s) s.size()
#define pb push_back
#define INF 1000001
#define MAX 1000001
#define pll pair<ll,ll>

int main(){
	std::ios::sync_with_stdio(false);
	ll n;
	in(n);
    bool f=true,f1=true;
    ll x1,y1;
    in2(x1,y1);
	for (int i = 1; i <n; ++i)
	{
		ll x,y;
		in2(x,y);
		if(x1 !=x){
            f=false;
        }
        if(y1!=y){
            f1=false;
        }
        x1=x,y1=y;
	}
    (f ||f1)?pr("YES"):pr("NO");
	
}