#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

#define all(a) (a).begin(), (a).end()
#define rall(a) (a).rbegin(), (a).rend()

const double EPS = 1e-9;
const ll INF = 1e17;

int main() {
	ios::sync_with_stdio(0);
	cin.tie(nullptr);
	cout.tie(nullptr);

	int n, px, py;
	cin >> n >> px >> py;

	bool b1 = 1, b2 = 1;
	n--;

	while (n--) {
		int x, y;
		cin >> x >> y;

		if (x != px) b1 = 0;
		if (y != py) b2 = 0;

		px = x;
		py = y;
	}

	cout << (b1 || b2 ? "YES" : "NO") << "\n";

	return 0;
}