//Author: Kevin
#include<bits/stdc++.h>
//#pragma GCC optimize("O2")
using namespace std;
#define ll long long
#define ull unsigned ll
#define pb emplace_back
#define mp make_pair
#define ALL(x) (x).begin(),(x).end()
#define rALL(x) (x).rbegin(),(x).rend()
#define srt(x) sort(ALL(x))
#define rev(x) reverse(ALL(x))
#define rsrt(x) sort(rALL(x))
#define sz(x) (int)(x.size())
#define inf 0x3f3f3f3f
#define pii pair<int,int>
#define lb(v,x) (int)(lower_bound(ALL(v),x)-v.begin())
#define ub(v,x) (int)(upper_bound(ALL(v),x)-v.begin())
#define uni(v) v.resize(unique(ALL(v))-v.begin())
#define longer __int128_t
void die(string S){puts(S.c_str());exit(0);}
ll n;
ll a,b;
ll A[5005],B[5005],C[5005],D[5005];
set<int> Rs[5005],Cs[5005];
bool vis[5005][5005];
void check(int x,int y)
{
	if(vis[x][y]&&!vis[x+1][y])
		Cs[y].insert(x);
	else
		Cs[y].erase(x);
	if(vis[x][y]&&!vis[x][y+1])
		Rs[x].insert(y);
	else
		Rs[x].erase(y);
	if(x&&vis[x-1][y]&&!vis[x][y])
		Cs[y].insert(x-1);
	else
		Cs[y].erase(x-1);
	if(y&&vis[x][y-1]&&!vis[x][y])
		Rs[x].insert(y-1);
	else
		Rs[x].erase(y-1);
}
int main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	cin>>n>>a>>b;
	for(int i=1;i<=n;i++)
	{
		cin>>A[i]>>B[i]>>C[i]>>D[i];
		A[i]-=a;
		B[i]-=a;
		C[i]-=b;
		D[i]-=b;
		A[i]=max(A[i],0ll);
		C[i]=max(C[i],0ll);
		B[i]=min(B[i],n);
		D[i]=min(D[i],n);
	}
	vis[0][0]=1;
	Rs[0].insert(0);
	Cs[0].insert(0);
	for(int i=1;i<=n;i++)
	{
		if(A[i]>B[i]||C[i]>D[i])
			continue;
		for(int j=A[i];j<=B[i];j++)
		{
			vector<int> vec;
			auto it=Rs[j].lower_bound(C[i]);
			while(it!=Rs[j].end()&&*it<=D[i])
			{
				vis[j][*it+1]=1;
				vec.pb(*it+1);
				it++;
			}
			for(auto k:vec)
				check(j,k);
		}
		for(int j=C[i];j<=D[i];j++)
		{
			vector<int> vec;
			auto it=Cs[j].lower_bound(A[i]);
			while(it!=Cs[j].end()&&*it<=B[i])
			{
				vis[*it+1][j]=1;
				vec.pb(*it+1);
				it++;
			}
			for(auto k:vec)
				check(k,j);
		}
	}
	int ans=0;
	for(int i=0;i<=n;i++)
		for(int j=0;j<=n;j++)
			if(vis[i][j])
				ans=max(ans,i+j);
	cout<<ans<<'\n';
	return 0;
}