#include <bits/stdc++.h>
using namespace std;
#define ll          unsigned long long int
#define mem(a,x)    memset(a,x,sizeof(a))
#define vi          vector<int>
#define vii         vector<vi>
#define pi          pair<int,int>
#define pii         pair<int,pi>
#define si(x)       scanf("%llu",&x)
#define sl(x)       scanf("%I64d",&x)
#define ss(s)       scanf("%s",s)
#define rep(i,a,b)  for(i=a;i<b;i++)
#define tr(it,container) for(auto it=container.begin();it!=container.end();++it)
#define F           first
#define S 			second
#define gc          getchar_unlocked
#define pb          push_back
#define mp          make_pair
#define all(a)      a.begin(),a.end()
#define sortall(a)  sort(all(a))
#define MOD			1000000007
#define N           100005
ll pwr(ll a,ll b,ll mod) {a%=mod;if(a<0)a+=mod;ll ans=1; while(b) {if(b&1) ans=(ans*a)%mod; a=(a*a)%mod; b/=2; } return ans; }
ll gcd(ll a,ll b) {while(b) {ll temp=a; a=b; b=temp%b; } return a; }

int main(){
	int n,x[20],y[20],a=0;
	cin>>n;
	for(int i=0;i<n;i++) cin>>x[i]>>y[i];
	bool ok=true;
	a=1;
	for(int i=1;i<n;i++){
		if(x[i] == x[0]) a++;
	}
	if(a ==n){
		cout<<"YES";
		return 0;
	}
	a = 1;
	for(int i=1;i<n;i++){
		if(y[i] == y[0]) a++;
	}
	if(a ==n){
		cout<<"YES";
		return 0;
	}
	cout<<"NO";
	return 0;
}