#include<bits/stdc++.h>
using namespace std;using ll=long long;
int rd(int x=0,char c=getchar()){int f=1;while(!isdigit(c))f=(c^'-'?1:-1),c=getchar();while(isdigit(c))x=x*10+(c^48),c=getchar();return x*f;}
const int N=5005;
int n,a,b;
int l1[N],r1[N],l2[N],r2[N];
bool f[N][N];
void output(){
	for(int i=0;i<N;puts(""),i++)for(int j=0;j<N;j++)cout<<f[i][j];
	puts("");
}
int main(){
	n=rd(),a=rd(),b=rd();
	for(int i=1;i<=n;i++)l1[i]=rd()-a,r1[i]=rd()-a,l2[i]=rd()-b,r2[i]=rd()-b;
	f[0][0]=1;
	for(int i=1;i<=n;i++)for(int x=N-1;~x;x--)for(int y=N-1;~y;y--){
		if(x)if(x-1>=l1[i]&&x-1<=r1[i])f[x][y]|=f[x-1][y];
		if(y)if(y-1>=l2[i]&&y-1<=r2[i])f[x][y]|=f[x][y-1];
		if(y)if(x>=l1[i]&&x<=r1[i])f[x][y]|=f[x][y-1];
		if(x)if(y>=l2[i]&&y<=r2[i])f[x][y]|=f[x-1][y];
	}
//	for(int i=1;i<=n;i++) 
	int ans=0;
	for(int i=0;i<N;i++)for(int j=0;j<N;j++)if(f[i][j])ans=max(ans,i+j);
	printf("%d",ans);
	return 0;
}