#include <iostream>
#include <vector>

using namespace std;

int main()
{
    int n;
    cin >> n;
    bool pole[n+2][2];
    for(int i = 0; i < n; i++){
        cin >> x >> y;
        pole[i][0] = false;
        pole[i][1] = false;
    }
    int x,y;
    for(int i = 0; i < n; i++){
        cin >> x >> y;
        pole[x-1][0] = true;
        pole[y-1][1] = true;
    }
    int pocet = 0;
        for (int i = 0; i < n; i++) {
            if (!pole[i][0]) {
                pocet++;

            }
            if (!pole[i][1]) {
                pocet++;
            }

        }
        cout << pocet;
}