//1171201016　稲村佑哉
//久々のC++での演習だったが、ゲーム形式で楽しく復習できた。
#include"bits/stdc++.h"
using namespace std;
#define LL long long

LL N,ans;
bool a[100];
vector<pair<LL, LL>> r,b;
pair<LL, LL>d;
int main() {
	cin >> N;
	vector<pair<LL, LL>> r, b;
	for (int i = 0; i < N; i++) {
		cin >> d.first >> d.second;
		r.push_back(d);
		a[i] = true;
	}

	for (int i = 0; i < N; i++) {
		cin >> d.first >> d.second;
		b.push_back(d);
	}
	sort(b.begin(), b.end());
	int c;
	int max_y;
	for (int i = 0; i < N; i++) {
		c = -1;
		max_y = -1;
		for (int j = 0; j < N; j++) {
			if (a[j]&&b[i].first > r[j].first&&b[i].second > r[j].second) {
				if (max_y < r[j].second) {
					max_y = r[j].second;
					c = j;
				}
			}
		}
		if (c >= 0) {
			a[c] = false;
			ans++;
		}
	}
	cout << ans << endl;
	return 0;

}
### Prompt

Please formulate 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
//1171201016　稲村佑哉
//久々のC++での演習だったが、ゲーム形式で楽しく復習できた。
#include"bits/stdc++.h"
using namespace std;
#define LL long long

LL N,ans;
bool a[100];
vector<pair<LL, LL>> r,b;
pair<LL, LL>d;
int main() {
	cin >> N;
	vector<pair<LL, LL>> r, b;
	for (int i = 0; i < N; i++) {
		cin >> d.first >> d.second;
		r.push_back(d);
		a[i] = true;
	}

	for (int i = 0; i < N; i++) {
		cin >> d.first >> d.second;
		b.push_back(d);
	}
	sort(b.begin(), b.end());
	int c;
	int max_y;
	for (int i = 0; i < N; i++) {
		c = -1;
		max_y = -1;
		for (int j = 0; j < N; j++) {
			if (a[j]&&b[i].first > r[j].first&&b[i].second > r[j].second) {
				if (max_y < r[j].second) {
					max_y = r[j].second;
					c = j;
				}
			}
		}
		if (c >= 0) {
			a[c] = false;
			ans++;
		}
	}
	cout << ans << endl;
	return 0;

}
```