#include <iostream>
#include <utility>
#include <algorithm>
int main(){
  int n,p,t,a=0,x,y,s[101]={},inf=1001001;
  std::cin>>n;
  std::pair<int,int> r[n],b[n];
  for(int i=0;i!=n;++i){std::cin>>x>>y;r[i]={x,y};}
  for(int i=0;i!=n;++i){std::cin>>x>>y;b[i]={x,y};}
  std::sort(r,r+n,std::greater<std::pair<int,int>>());
  std::sort(b,b+n);
  for(int i=0;i!=n;++i){
    t=inf;
    p=inf;
    for(int j=0;j!=n;++j){
      if(s[j]==0&&b[j].first>r[i].first){
        if(b[j].second<t&&b[j].second>r[i].second){
          t=b[j].second;
          p=j;
        }
      }
    }
    if(p<inf){
      ++s[p];
      ++a;
    }
  }
  std::cout<<a<<"\n";
}
  
  
### Prompt

Your challenge is to write 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 <iostream>
#include <utility>
#include <algorithm>
int main(){
  int n,p,t,a=0,x,y,s[101]={},inf=1001001;
  std::cin>>n;
  std::pair<int,int> r[n],b[n];
  for(int i=0;i!=n;++i){std::cin>>x>>y;r[i]={x,y};}
  for(int i=0;i!=n;++i){std::cin>>x>>y;b[i]={x,y};}
  std::sort(r,r+n,std::greater<std::pair<int,int>>());
  std::sort(b,b+n);
  for(int i=0;i!=n;++i){
    t=inf;
    p=inf;
    for(int j=0;j!=n;++j){
      if(s[j]==0&&b[j].first>r[i].first){
        if(b[j].second<t&&b[j].second>r[i].second){
          t=b[j].second;
          p=j;
        }
      }
    }
    if(p<inf){
      ++s[p];
      ++a;
    }
  }
  std::cout<<a<<"\n";
}
  
  
```