#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

struct Rectangle{
    int length;
    int width;
};

bool operator<(const Rectangle& lhs, const Rectangle& rhs) {
    if (lhs.length == rhs.length) {
        return lhs.width < rhs.width;
    }
    return lhs.length < rhs.length;
}

int main() {
    int n;
    cin >> n;

    vector<Rectangle> rectangles(n);
    for (int i = 0; i < n; ++i) {
        int length = 0;
        int width = 0;
        cin >> length >> width;
        if (length < width) {
            swap(length, width);
        }
        rectangles[i] = {length, width};
    }

    sort(rectangles.begin(), rectangles.end());
    rectangles.push_back({1000000500, 0});

    int max_width_of_rectangles_with_cur_length = 0;
    int max_width_of_long_rectangles = 0;
    int ans = 0;

    for (int i = n - 1; i >= 0; --i) {
        if (rectangles[i].length != rectangles[i + 1].length) {
            max_width_of_long_rectangles = max(
                    max_width_of_long_rectangles,
                    max_width_of_rectangles_with_cur_length
            );
            max_width_of_rectangles_with_cur_length = rectangles[i].width;
        }
        if (!(rectangles[i].width < max_width_of_long_rectangles)) {
            ans++;
        }
    }

    cout << ans << endl;

    return 0;
}