#include<bits/stdc++.h>
using namespace std;
struct ee
{
	int x,y;
}a[121],b[121];
bool f[121];
int n,p=1,len=1,ans;
bool mycmp(ee q,ee w)
{
	return q.x<w.x;
}
int main()
{
	cin>>n;
	for(int i=1;i<=n;i++)
	cin>>a[i].x>>a[i].y;
	for(int i=1;i<=n;i++)
	cin>>b[i].x>>b[i].y;
	sort(a+1,a+1+n,mycmp);
	sort(b+1,b+1+n,mycmp);
	for(int i=n;i>=1;i--)
	{
		int maxx=10000,t=0;
		for(int j=n;j>=1;j--)
		{
		if(a[i].x>b[j].x) break;
		if(!f[j]&&a[i].y<b[j].y) 
		{
		if(b[j].y<=maxx) maxx=b[j].y,t=j;
		}
		}
	    if(t!=0) f[t]=1,ans++;
	}
	
	/*while(1)
	{
		if(p>n||len>n) break;
		
		if(a[p].x<b[len].x&&a[p].y<b[len].y) {ans++;p++;len++;continue;}
		if(a[p].x>b[) len++;
	}*/
	cout<<ans;
	return 0;
}
### Prompt

Please formulate a Cpp solution to the following problem:

On a two-dimensional plane, there are N red points and N blue points. The coordinates of the i-th red point are (a_i, b_i), and the coordinates of the i-th blue point are (c_i, d_i).

A red point and a blue point can form a friendly pair when, the x-coordinate of the red point is smaller than that of the blue point, and the y-coordinate of the red point is also smaller than that of the blue point.

At most how many friendly pairs can you form? Note that a point cannot belong to multiple pairs.

Constraints

* All input values are integers.
* 1 \leq N \leq 100
* 0 \leq a_i, b_i, c_i, d_i < 2N
* a_1, a_2, ..., a_N, c_1, c_2, ..., c_N are all different.
* b_1, b_2, ..., b_N, d_1, d_2, ..., d_N are all different.

Input

Input is given from Standard Input in the following format:


N
a_1 b_1
a_2 b_2
:
a_N b_N
c_1 d_1
c_2 d_2
:
c_N d_N


Output

Print the maximum number of friendly pairs.

Examples

Input

3
2 0
3 1
1 3
4 2
0 4
5 5


Output

2


Input

3
0 0
1 1
5 2
2 3
3 4
4 5


Output

2


Input

2
2 2
3 3
0 0
1 1


Output

0


Input

5
0 0
7 3
2 2
4 8
1 6
8 5
6 9
5 4
9 1
3 7


Output

5


Input

5
0 0
1 1
5 5
6 6
7 7
2 2
3 3
4 4
8 8
9 9


Output

4

### Response

```cpp
#include<bits/stdc++.h>
using namespace std;
struct ee
{
	int x,y;
}a[121],b[121];
bool f[121];
int n,p=1,len=1,ans;
bool mycmp(ee q,ee w)
{
	return q.x<w.x;
}
int main()
{
	cin>>n;
	for(int i=1;i<=n;i++)
	cin>>a[i].x>>a[i].y;
	for(int i=1;i<=n;i++)
	cin>>b[i].x>>b[i].y;
	sort(a+1,a+1+n,mycmp);
	sort(b+1,b+1+n,mycmp);
	for(int i=n;i>=1;i--)
	{
		int maxx=10000,t=0;
		for(int j=n;j>=1;j--)
		{
		if(a[i].x>b[j].x) break;
		if(!f[j]&&a[i].y<b[j].y) 
		{
		if(b[j].y<=maxx) maxx=b[j].y,t=j;
		}
		}
	    if(t!=0) f[t]=1,ans++;
	}
	
	/*while(1)
	{
		if(p>n||len>n) break;
		
		if(a[p].x<b[len].x&&a[p].y<b[len].y) {ans++;p++;len++;continue;}
		if(a[p].x>b[) len++;
	}*/
	cout<<ans;
	return 0;
}
```