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

const int N=505;
int n,a,b,la[N],ra[N],lb[N],rb[N];

bool dp[N][N][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][0]=1;
	for(int i=0;i<n;i++)if(la[i+1]<=ra[i+1]&&lb[i+1]<=rb[i+1])
		for(int j=0;j<n;j++)for(int k=0;k<n;k++){
			dp[i+1][j][k]|=dp[i][j][k];
			if(la[i+1]<=j&&j<=ra[i+1]&&lb[i+1]<=k&&k<=rb[i+1]){
				dp[i+1][j+1][k]|=dp[i][j][k];
				dp[i+1][j][k+1]|=dp[i][j][k];
			}
		}
	int res=0;
	for(int j=0;j<n;j++)for(int k=0;k<n;k++)if(dp[n][j][k])res=max(res,j+k);
	printf("%d\n",res);
	return 0;
}