#include <bits/stdc++.h>
//#define int long long
#define fi first
#define se second 
#define pb push_back
#define ott(i, l, r) for (register int i = (l); i <= (r); i ++)
#define tto(i, l, r) for (register int i = (r); i >= (l); i --)
using namespace std;
typedef long long ll;
typedef long double ld;
int read () {
	int x = 0; bool f = false; char c = getchar ();
	while (!isdigit (c)) f |= (c == '-'), c = getchar ();
	while (isdigit (c)) x = (x << 3) + (x << 1) + (c ^ 48), c = getchar ();
	return f ? -x : x;
}
const int N = 5500, mod = 1e9 + 7;
int n, s1, s2, res;
int vis[N][N]; bool ins[N][N];
vector <pair <int, int> > cac;
inline void add (const int &x, const int &y) {
	if (!vis[x + 1][y]) cac.pb ({x + 1, y}), vis[x + 1][y] = true;
	if (!vis[x][y + 1]) cac.pb ({x, y + 1}), vis[x][y + 1] = true;
	return ;
}
struct Segment_tree {
	int cnt, id; int siz[N];
	#define ls p << 1
	#define rs p << 1 | 1
	void pup (int p) {
		return void (siz[p] = siz[ls] + siz[rs]);
	}
	void ins (int x, int p = 1, int l = 0, int r = n) {
		if (l >= r) return void (++ siz[p]);
		int mid = l + r >> 1;
		x <= mid ? ins (x, ls, l, mid) : ins (x, rs, mid + 1, r);
		return pup (p);
	}
	void del (int x, int y, int p = 1, int l = 0, int r = n) {
		if (!siz[p]) return ;
		if (l >= r) {
			add (id, l); return void (-- siz[p]);
		}
		int mid = l + r >> 1;
		if (x <= mid) del (x, y, ls, l, mid); if (y > mid) del (x, y, rs, mid + 1, r);
		return pup (p);
	}
} has[N];
int main () {
	n = read (), s1 = read (), s2 = read ();
	ott (i, 0, n) has[i].id = i;
	vis[0][0] = true, has[0].ins (0);
	ott (i, 1, n) {
		register int l1 = read () - s1, r1 = read () - s1, l2 = read () - s2, r2 = read () - s2;
		if (l1 < 0) l1 = 0; if (l2 < 0) l2 = 0; if (r1 > n) r1 = n; if (r2 > n) r2 = n;
		if (l2 <= r2) ott (x, l1, r1) has[x].del (l2, r2);
		for (auto &[x, y] : cac) has[x].ins (y); cac.clear ();
	}
	ott (i, 0, n)
		ott (j, 0, n - i)
		    if (vis[i][j]) 
		    	res = max (res, i + j);
	printf ("%d\n", res);
    return 0;
}