#include<iostream>
#include<cstdio>
#include<vector>
#include<set>
#include<queue>
#include<algorithm>
#include<cstring>
using namespace std;

int main() {
	int n, x, y, x2, y2;
	bool horizontal = true, vertical = true;
	cin >> n;
	n--;

	cin >> x2 >> y2;
	while (n--) {
		cin >> x >> y;
		if (x != x2)
			horizontal = false;
		if (y != y2)
			vertical = false;
		x2 = x; y2 = y;
	}

	if (horizontal || vertical)
		cout << "YES\n";
	else
		cout << "NO\n";

	return 0;
}