#include<cstdio>
#include<cstdlib>
#include<algorithm>
#include<iostream>
#include<map>
#include<vector>
#include <bitset>
#include<math.h>
#include<queue>
using namespace std;
#define MAX 300000
#define INF 3000
typedef long long ll;
typedef pair<int,int> P;




int main(){
  int N,a,b;
  cin>>N;
  P A[200],B[200];
  for(int i=0;i<N;i++){
    cin>>a>>b;
    A[i]=make_pair(a,b);
  }
  for(int i=0;i<N;i++){
    cin>>a>>b;
    B[i]=make_pair(a,b);
  }

  sort(B,B+N);

  int temp=-1,num,ans=0;

  for(int i=0;i<N;i++,temp=-1){
    for(int j=0;j<N;j++){
      if(B[i].first>A[j].first && temp<A[j].second && B[i].second>A[j].second){
        temp=A[j].second;
        num=j;
      }
    }
    if(temp!=-1){
      ans++;
      A[num].first=1000;
    }
  }
  cout<<ans<<endl;
}

### Prompt

Your task is to create 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<cstdio>
#include<cstdlib>
#include<algorithm>
#include<iostream>
#include<map>
#include<vector>
#include <bitset>
#include<math.h>
#include<queue>
using namespace std;
#define MAX 300000
#define INF 3000
typedef long long ll;
typedef pair<int,int> P;




int main(){
  int N,a,b;
  cin>>N;
  P A[200],B[200];
  for(int i=0;i<N;i++){
    cin>>a>>b;
    A[i]=make_pair(a,b);
  }
  for(int i=0;i<N;i++){
    cin>>a>>b;
    B[i]=make_pair(a,b);
  }

  sort(B,B+N);

  int temp=-1,num,ans=0;

  for(int i=0;i<N;i++,temp=-1){
    for(int j=0;j<N;j++){
      if(B[i].first>A[j].first && temp<A[j].second && B[i].second>A[j].second){
        temp=A[j].second;
        num=j;
      }
    }
    if(temp!=-1){
      ans++;
      A[num].first=1000;
    }
  }
  cout<<ans<<endl;
}

```