#include <bits/stdc++.h>
using namespace std;
typedef long long int ll;

int main() {

	int n;
	cin >> n;
	int x[10], y[10];
	int xf = 0, yf = 0, xc = 0, yc = 0;
	for(int i = 0; i < n; i++) {
		cin >> x[i] >> y[i];
		if(i == 0) {
			xf = x[i];
			yf = y[i];
			xc++;
			yc++;
		}
		else {
			if(x[i] == xf)	xc++;
			if(y[i] == yf)	yc++;
		}
	}

	if(xc == n or yc == n)
		cout << "YES";
	else
		cout << "NO";
	return 0;
}