#include <bits/stdc++.h>
using namespace std;
int main(){
	int n;
	cin>>n;
	int x[n],y[n];
	for(int i=0;i<n;i++){
		cin>>x[i]>>y[i];
	} 
	int a=x[0],b=y[0];
	int countx=1,county=1;
	for(int i=1;i<n;i++){
		if(x[i]==a)
			countx++;
		if(y[i]==b)
			county++;
	}
	if(countx==n||county==n)
		cout<<"YES";
	else
		cout<<"NO";
	return 0;
}