#include <iostream>
#include <algorithm>
#include <functional>
#include<vector>
#include<math.h>
using namespace std;


int main() {
	int N;
	int Y = 0;
	cin >> N;
	pair<int, int> ab[101];
	pair<int, int> cd[101];



	for (int i = 0; i < N; i++) {
		cin >> ab[i].first >> ab[i].second;
	}
	for (int i = 0; i < N; i++) {
		cin >> cd[i].first >> cd[i].second;
	}

	sort(ab, ab + N);
	sort(cd, cd + N);

	for (int i = 0; i<N; i++) {
		int R = -1;
		int W = -1;
		
		for (int k = N - 1; k >= 0; k--) {
			
			if (cd[i].first > ab[k].first&&cd[i].second > ab[k].second) {
				
				if (R<ab[k].second) {
					R = ab[k].second;
					W = k;
					
				}
			}
		}
		if (W >= 0) {
			ab[W].second = 100000;
			Y++;
		
		}
	
	}



	cout << Y << endl;

	return 0;
}


### Prompt

Generate 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 <algorithm>
#include <functional>
#include<vector>
#include<math.h>
using namespace std;


int main() {
	int N;
	int Y = 0;
	cin >> N;
	pair<int, int> ab[101];
	pair<int, int> cd[101];



	for (int i = 0; i < N; i++) {
		cin >> ab[i].first >> ab[i].second;
	}
	for (int i = 0; i < N; i++) {
		cin >> cd[i].first >> cd[i].second;
	}

	sort(ab, ab + N);
	sort(cd, cd + N);

	for (int i = 0; i<N; i++) {
		int R = -1;
		int W = -1;
		
		for (int k = N - 1; k >= 0; k--) {
			
			if (cd[i].first > ab[k].first&&cd[i].second > ab[k].second) {
				
				if (R<ab[k].second) {
					R = ab[k].second;
					W = k;
					
				}
			}
		}
		if (W >= 0) {
			ab[W].second = 100000;
			Y++;
		
		}
	
	}



	cout << Y << endl;

	return 0;
}


```