#include <bits/stdc++.h>
using i64 = long long;

inline void chkmax(int &a, const int &b) {if (a < b) a = b;}
inline void chkmin(int &a, const int &b) {if (a > b) a = b;}
constexpr int N = 5010;

int n, x, y;
std::set<int> pset[N];
std::set<std::pair<int, int>> st;

int main() {
#ifdef HeratinoNelofus
	freopen("input.txt", "r", stdin);
#endif
	std::ios::sync_with_stdio(false);
	std::cin.tie(nullptr);
	
	std::cin >> n >> x >> y;
	pset[0].insert(0);

	int ans = 0;
	auto check = [&](int p, int q) {
		return st.find(std::make_pair(p, q)) == st.end();
	};
	auto process = [&](int p, int q) {
		pset[p].erase(q);
		st.insert(std::make_pair(p, q));
		if (check(p + 1, q))
			pset[p + 1].insert(q);
		if (check(p, q + 1))
			pset[p].insert(q + 1);
		chkmax(ans, (p - x) + (q - y) + 1);
	};

	for (int i = 1; i <= n; i++) {
		int xl, xh, yl, yh;
		std::cin >> xl >> xh;
		std::cin >> yl >> yh;
		xl = std::max(xl - x, 0);
		xh = std::min(xh - x, n);
		yl = std::max(yl - y, 0);
		yh = std::min(yh - y, n);
		if (xl > xh || yl > yh)
			continue;
		for (int p = xl; p <= xh; p++) {
			auto qit = pset[p].lower_bound(yl);
			if (qit == pset[p].end())
				continue;
			int q = *qit;
			if (q > yh)
				continue;
			process(p, q);
		}
	}
	std::cout << ans << '\n';
	return 0;
}