#include<bits/stdc++.h>
using namespace std;
#define inf 1e9
#define ll long long 
#define M 1000000007
#define P pair<int,int>
#define FOR(i,m,n) for(int i=m;i<n;i++)
#define rep(i,n) FOR(i,0,n)
const int vx[4] = {0,1,0,-1};
const int vy[4] = {1,0,-1,0};
#define PI 3.14159265

int n;
bool c[200][200];
int ans;

int main(){
  cin>>n;
  rep(i,n){
    int a,b;
    cin>>a>>b;
    c[b][a] = true;
  }
  vector<P> v;

  rep(i,n){
    int a,b;
    cin>>a>>b;
    v.push_back(P(b,a));
  }

  sort(v.begin(),v.end());

  rep(i,n){
    P p = v[i];
    int x=-1,y=-1;
    rep(j,p.second){
      rep(k,p.first){
        if(c[k][j]){
          x = j; y =k;
        }
      }
    }
    if(x!=-1){
      c[y][x] = false;
      ans++;
    }
  }

  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 inf 1e9
#define ll long long 
#define M 1000000007
#define P pair<int,int>
#define FOR(i,m,n) for(int i=m;i<n;i++)
#define rep(i,n) FOR(i,0,n)
const int vx[4] = {0,1,0,-1};
const int vy[4] = {1,0,-1,0};
#define PI 3.14159265

int n;
bool c[200][200];
int ans;

int main(){
  cin>>n;
  rep(i,n){
    int a,b;
    cin>>a>>b;
    c[b][a] = true;
  }
  vector<P> v;

  rep(i,n){
    int a,b;
    cin>>a>>b;
    v.push_back(P(b,a));
  }

  sort(v.begin(),v.end());

  rep(i,n){
    P p = v[i];
    int x=-1,y=-1;
    rep(j,p.second){
      rep(k,p.first){
        if(c[k][j]){
          x = j; y =k;
        }
      }
    }
    if(x!=-1){
      c[y][x] = false;
      ans++;
    }
  }

  cout<<ans<<endl;

  return 0;
}



```