#include <iostream>
#include <vector>
#include <algorithm>
#include <string>
#include <map>
using namespace std;

int main()
{
	int n; cin >> n;
	vector<pair<int, int>>X;
	X.reserve(2 * n);
	for (int i = 0; i < n; i++) {
		int r0, r1, c0, c1;
		cin >> r0 >> c0 >> r1 >> c1;
		X.push_back(make_pair(r0, c0));
		X.push_back(make_pair(r1, c1));
	}
	sort(X.begin(), X.end());
	int cnt = 0;
	bool flag = true;
	for (int i = 1; i < 2 * n; i++) {
		if (X[i] == X[i - 1]) {
			cnt++;
		}
		else {
			if (cnt >= 2)flag = false;
			cnt = 0;
		}
	}
	if (cnt > 2)flag = false;

	if (flag)cout << "YES" << endl;
	else cout << "NO" << endl;

    return 0;
}