#include<bits/stdc++.h>
using namespace std;
#define MOD 1000000007
#define BIG 1000000010
#define EPS 1e-9
#define fst first
#define scd second

#define repi(i,x,n) for(int i=x;i<n;i++)
#define rep(i,n) repi(i,0,n)
#define repn(i,n) for(int i=n;i>=0;i--)
#define int long long


signed main(){
  int n;
  cin>>n;
  int x,y;
  pair<int,int> a[100],b[100];
  rep(i,n){
    cin>>x>>y;
    a[i]=make_pair(y,x);
  }
  rep(i,n){
    cin>>x>>y;
    b[i]=make_pair(x,y);
  }
  sort(a,a+n);
 
  sort(b,b+n);
  
  int flagb[100]={0};
  int ans=0;
 
  rep(i,n){
    repn(j,n-1){
      if(a[j].fst<b[i].scd && a[j].scd<b[i].fst && flagb[j]==0){
	//	cout<<i<<" "<<j<<endl;
	flagb[j]=1;
	ans++;
	break;
      }
    }
  }
  cout<<ans<<endl;
  return 0;
}









### Prompt

In cpp, your task is to solve 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;
#define MOD 1000000007
#define BIG 1000000010
#define EPS 1e-9
#define fst first
#define scd second

#define repi(i,x,n) for(int i=x;i<n;i++)
#define rep(i,n) repi(i,0,n)
#define repn(i,n) for(int i=n;i>=0;i--)
#define int long long


signed main(){
  int n;
  cin>>n;
  int x,y;
  pair<int,int> a[100],b[100];
  rep(i,n){
    cin>>x>>y;
    a[i]=make_pair(y,x);
  }
  rep(i,n){
    cin>>x>>y;
    b[i]=make_pair(x,y);
  }
  sort(a,a+n);
 
  sort(b,b+n);
  
  int flagb[100]={0};
  int ans=0;
 
  rep(i,n){
    repn(j,n-1){
      if(a[j].fst<b[i].scd && a[j].scd<b[i].fst && flagb[j]==0){
	//	cout<<i<<" "<<j<<endl;
	flagb[j]=1;
	ans++;
	break;
      }
    }
  }
  cout<<ans<<endl;
  return 0;
}









```