#include <bits/stdc++.h>
#define ll long long
#define F first
#define S second
#define y1 qwe_y1
#define y2 qwe_y2
using namespace std;
const ll INF = 1e9 + 7;

map<ll, ll> mp1, mp2;
ll a, b, n;
int main(){
	ios_base::sync_with_stdio(false);
	cin >> n;
	for(int i = 1; i <= n; i++){
		cin >> a >> b;
		mp1[a] = 1;
		mp2[b] = 1;
	}
	if(mp1.size() == 1 || mp2.size() == 1){
		cout << "YES";
	} else {
		cout << "NO";
	}
}