#include <iostream>
#include <vector>
#include <algorithm>
#include <string>
#include <map>
using namespace std;
int A[10001];

int main()
{
	int n; cin >> n;
	vector<pair<int, int>>X,Y;
	X.reserve(n);
	for (int i = 0; i < n; i++) {
		int r0, r1, c0, c1;
		cin >> r0 >> c0 >> r1 >> c1;
		X.push_back(make_pair(r0*100+c0, r1*100+c1));
	}

	for (int i = 0; i < n; i++) {
		A[X[i].first]++;
		A[X[i].second]++;
	}

	for (int i = 0; i < X.size(); i++) {
		if (A[X[i].first] == 1 || A[X[i].second] == 1) {
			X.erase(X.begin() + i);
			i--;
		}
	}

	int cnt = 0; bool flag = true;
	for (int i = 0; i < X.size(); i++) {
		Y.push_back(make_pair(X[i].first / 100, X[i].first % 100));
		Y.push_back(make_pair(X[i].second / 100, X[i].second % 100));
	}
	sort(Y.begin(), Y.end());
	for (int i = 1; i < Y.size(); i++) {
		if (Y[i] == Y[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;
}