/*
ID: cmykrgb1
PROG: picture
LANG: C++
*/

#include <iostream>
#include <fstream>
#define MAX 10001

using namespace std;

typedef struct 
{
	int s,t,p;
	bool start;
}Line;

ifstream fi("picture.in");
ofstream fo("picture.out");

int N,ans=0;
int *level;
Line Lx[MAX],Ly[MAX];

inline int cmp(const void *a,const void *b)
{
	if (((Line*)a)->p==((Line*)b)->p)
	{
		if (((Line*)a)->start)
			return -1;
		else
			return 1;
	}
	return ((Line *)a)->p < ((Line *)b)->p ? -1 : 1;
}

void init()
{
	int i,x1,x2,y1,y2;
	fi >> N;
	for (i=1;i<=N;i++)
	{
		fi >> x1 >> y2 >> x2 >> y1;
		Lx[i*2-1].p=y1;
		Lx[i*2-1].s=x1;
		Lx[i*2-1].t=x2;
		Lx[i*2-1].start=false;
		Lx[i*2].p=y2;
		Lx[i*2].s=x1;
		Lx[i*2].t=x2;
		Lx[i*2].start=true;
		Ly[i*2-1].p=x1;
		Ly[i*2-1].s=y2;
		Ly[i*2-1].t=y1;
		Ly[i*2-1].start=true;
		Ly[i*2].p=x2;
		Ly[i*2].s=y2;
		Ly[i*2].t=y1;
		Ly[i*2].start=false;
	}
	N*=2;
	qsort(Lx+1,N,sizeof(Lx[0]),cmp);
	qsort(Ly+1,N,sizeof(Ly[0]),cmp);
	level=(int *)malloc(sizeof(int)*20002);
	level+=10000;
}

void Scan(Line *L)
{
	int i,j;
	for (i=-10000;i<=10000;i++)
		level[i]=0;
	for (i=1;i<=N;i++)
	{
		if (L[i].start)
		{
			for (j=L[i].s;j<L[i].t;j++)
			{
				level[j]++;
				if (level[j]==1)
					ans++;
			}
		}
		else
		{
			for (j=L[i].s;j<L[i].t;j++)
			{
				level[j]--;
				if (level[j]==0)
					ans++;
			}
		}
	}
}

void print()
{
	fo << ans << endl;
	fi.close();
	fo.close();
}

int main()
{
	init();
	Scan(Lx);
	Scan(Ly);
	print();
	return 0;
}