#include <stdio.h>
#include <iostream>
#include <stdlib.h>
#include <algorithm>
#include <math.h>
#include <vector>
#include <queue>
#include <string.h>
#include <string>

using namespace std;
typedef pair <int, int> pp;
#define MAXN 100005
#define MAXM 1005

int N, M;
pp ar[MAXN];
int main(void)
{
	cin >> N;
	for(int i=0; i<N; i++) cin >> ar[i].first >> ar[i].second;
	int x = ar[0].first, y = ar[0].second;
	int f = 0;
	for(int i=0; i<N; i++) {
		if(ar[i].first != x) f = 1;
	}
	if(f == 0) {
		printf("YES\n");
		return 0;
	}
	for(int i=0; i<N; i++) {
		if(ar[i].second != y) f = 2;
	}
	if(f != 2) {
		printf("YES\n");
		return 0;
	}
	printf("NO\n");
	return 0;	
}