#include<bits/stdc++.h>
using namespace std;

const int N=5005;
int n,a,b,la[N],ra[N],lb[N],rb[N];

typedef bitset<N> bs;
bs dp[2][N];
int main(){
	scanf("%d%d%d",&n,&a,&b);
	for(int i=1;i<=n;i++){
		scanf("%d%d%d%d",&la[i],&ra[i],&lb[i],&rb[i]);
		la[i]=max(0,la[i]-a);
		ra[i]=min(n-1,ra[i]-a);
		lb[i]=max(0,lb[i]-b);
		rb[i]=min(n-1,lb[i]-b);
	}
	dp[0][0].set(0);
	for(int i=0;i<n;i++){
		bool o=i&1;
		if(la[i+1]>ra[i+1]||lb[i+1]>rb[i+1])continue;
		for(int j=0;j<n;j++)dp[!o][j].reset();
		for(int j=0;j<n;j++){
			dp[!o][j]|=dp[o][j];
			if(la[i+1]<=j&&j<=ra[i+1]){
				bs tmp=dp[o][j];
				tmp>>=lb[i+1];
				tmp<<=N-rb[i+1]+lb[i+1]-1;
				tmp>>=N-rb[i+1]-1;
				dp[!o][j+1]|=tmp;
				dp[!o][j]|=tmp<<1;
			}
		}
	}
	int res=0;
	for(int j=0;j<n;j++)for(int k=0;k<n;k++)if(dp[n&1][j][k])res=max(res,j+k);
	printf("%d\n",res);
	return 0;
}