#include<bits/stdc++.h>
#define int long long
using namespace std;
const int N=5005;
const int inf=2e9+7;

static char buf[1000000],*p1=buf,*p2=buf;
#define getchar() p1==p2&&(p2=(p1=buf)+fread(buf,1,1000000,stdin),p1==p2)?EOF:*p1++
inline int wrd(){int x=0,f=1;char c=getchar();while(c<'0' || c>'9'){if(c=='-') f=-1;c=getchar();}while(c>='0' && c<='9') {x=(x<<3)+(x<<1)+c-48;c=getchar();}return x*f;}
inline void write(int x){static char buf[20];static int len=-1;if(x<0)putchar('-'),x=-x;do buf[++len]=x%10,x/=10;while(x);while(len>=0)putchar(buf[len--]+48);}

int n,sx,sy,l[N],r[N],as;

signed main(){
	n=wrd(),sx=wrd(),sy=wrd();
	memset(r,-1,sizeof r),l[0]=r[0]=sy;
	for(int i=1;i<=n;++i){
		int lx=wrd(),rx=wrd(),ly=wrd(),ry=wrd();
		for(int j=i-1;~j;--j){
			if(sx+j<lx || sx+j>rx) continue;
			int L=max(ly,l[j]),R=min(ry,r[j]);
			if(L<=R){
				r[j]=max(r[j],R+1);
				if(l[j+1]>r[j+1]) l[j+1]=L,r[j+1]=R;
				else r[j+1]=max(r[j+1],R);
			}
		}
	}
	for(int i=0;i<=n;++i) if(l[i]<=r[i]) as=max(as,i+r[i]-sy);
	return write(as),0;
}