#include<bits/stdc++.h>
#define pb emplace_back
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

#pragma GCC optimize(3,"Ofast")
#pragma GCC optimize(3)
#pragma GCC target("avx")
#pragma GCC optimize("Ofast")
#pragma GCC optimize("inline")
#pragma GCC optimize("-fgcse")
#pragma GCC optimize("-fgcse-lm")
#pragma GCC optimize("-fipa-sra")
#pragma GCC optimize("-ftree-pre")
#pragma GCC optimize("-ftree-vrp")
#pragma GCC optimize("-fpeephole2")
#pragma GCC optimize("-ffast-math")
#pragma GCC optimize("-fsched-spec")
#pragma GCC optimize("unroll-loops")
#pragma GCC optimize("-falign-jumps")
#pragma GCC optimize("-falign-loops")
#pragma GCC optimize("-falign-labels")
#pragma GCC optimize("-fdevirtualize")
#pragma GCC optimize("-fcaller-saves")
#pragma GCC optimize("-fcrossjumping")
#pragma GCC optimize("-fthread-jumps")
#pragma GCC optimize("-funroll-loops")
#pragma GCC optimize("-fwhole-program")
#pragma GCC optimize("-freorder-blocks")
#pragma GCC optimize("-fschedule-insns")
#pragma GCC optimize("inline-functions")
#pragma GCC optimize("-ftree-tail-merge")
#pragma GCC optimize("-fschedule-insns2")
#pragma GCC optimize("-fstrict-aliasing")
#pragma GCC optimize("-fstrict-overflow")
#pragma GCC optimize("-falign-functions")
#pragma GCC optimize("-fcse-skip-blocks")
#pragma GCC optimize("-fcse-follow-jumps")
#pragma GCC optimize("-fsched-interblock")
#pragma GCC optimize("-fpartial-inlining")
#pragma GCC optimize("no-stack-protector")
#pragma GCC optimize("-freorder-functions")
#pragma GCC optimize("-findirect-inlining")
#pragma GCC optimize("-fhoist-adjacent-loads")
#pragma GCC optimize("-frerun-cse-after-loop")
#pragma GCC optimize("inline-small-functions")
#pragma GCC optimize("-finline-small-functions")
#pragma GCC optimize("-ftree-switch-conversion")
#pragma GCC optimize("-foptimize-sibling-calls")
#pragma GCC optimize("-fexpensive-optimizations")
#pragma GCC optimize("-funsafe-loop-optimizations")
#pragma GCC optimize("inline-functions-called-once")
#pragma GCC optimize("-fdelete-null-pointer-checks")
#pragma GCC optimize(2)

using namespace std;
using namespace __gnu_pbds;

int n,a,b;
int l1[5010],r1[5010],l2[5010],r2[5010];
bool vis[5010][5010];
vector<pair<int,int> > add,del;
struct node
{
	int l,r;
	__gnu_pbds::tree<std::pair<int, int>, __gnu_pbds::null_type,
                 std::less<std::pair<int, int> >, __gnu_pbds::rb_tree_tag,
                 __gnu_pbds::tree_order_statistics_node_update> s;
}tr[20010];
inline void pushup(int u)
{
	tr[u].s.clear();
	for(auto o:tr[u<<1].s) tr[u].s.insert(o);
	for(auto o:tr[u<<1|1].s) tr[u].s.insert(o);
}
void build(int u,int l,int r)
{
	tr[u]={l,r};
	if(tr[u].l==tr[u].r)
	{
		if(tr[u].l==0) tr[u].s.insert({0,0});
		return;
	}int mid=l+r>>1;
	build(u<<1,l,mid);build(u<<1|1,mid+1,r);
	pushup(u);
}
void modify_d(int u,int x,int y)
{
	if(tr[u].l==tr[u].r) return tr[u].s.insert(make_pair(y,x)),void();
	int mid=tr[u].l+tr[u].r>>1;
	if(x<=mid) modify_d(u<<1,x,y);
	else modify_d(u<<1|1,x,y);
	pushup(u);
}
inline void ads(int x,int y)
{
	if(vis[x][y]) return;
	vis[x][y]=1;
	add.pb(make_pair(y,x));
}
void modify(int u,int l,int r,int l1,int r1)
{
	if(tr[u].l>=l&&tr[u].r<=r)
	{
		auto o=tr[u].s.lower_bound(make_pair(l1,0)),p=tr[u].s.lower_bound(make_pair(r1+1,0));
		for(auto i=o;i!=p;i++) del.pb(*i);
		for(auto o:del) tr[u].s.erase(o),ads(o.first+1,o.second),ads(o.first,o.second+1);
		del.clear();
		return;
	}
	int mid=tr[u].l+tr[u].r>>1;
	if(l<=mid) modify(u<<1,l,r,l1,r1);
	else modify(u<<1|1,l,r,l1,r1);
	pushup(u);
}
void ad()
{
	for(auto o:add) modify_d(1,o.first,o.second);
	add.clear();
}
bool ck(int i)
{
	if(l1[i]<0||l2[i]<0) return 1;
	if(r1[i]>n||r2[i]>n) return 1;
	return 0; 
}
int main()
{
	ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
	cin>>n>>a>>b;
	for(int i=1;i<=n;i++) cin>>l1[i]>>r1[i]>>l2[i]>>r2[i],l1[i]-=a,r1[i]-=a,l2[i]-=b,r2[i]-=b;
	build(1,0,n);vis[0][0]=1;
	for(int i=1;i<=n;i++)
	{
		if(ck(i)) continue;
		modify(1,l1[i],r1[i],l2[i],r2[i]);
		ad();
	}
	int ans=0;
	for(int i=1;i<=n;i++)
	{
		for(int j=1;j<=n;j++) if(vis[i][j]) ans=max(ans,i+j);
	}cout<<ans;
	return 0;
}