#include <bits/stdc++.h>

#define FOR(i,a,b) for(int i= (a); i<((int)b); ++i)
#define RFOR(i,a) for(int i=(a); i >= 0; --i)
#define FOE(i,a) for(auto i : a)
#define ALL(c) (c).begin(), (c).end()
#define RALL(c) (c).rbegin(), (c).rend()
#define DUMP(x)  cerr << #x << " = " << (x) << endl;
#define SUM(x) std::accumulate(ALL(x), 0LL)
#define MIN(v) *std::min_element(v.begin(), v.end())
#define MAX(v) *std::max_element(v.begin(), v.end())
#define EXIST(v,x) (std::find(v.begin(), v.end(), x) != v.end())
#define BIT(n) (1LL<<(n))
#define UNIQUE(v) v.erase(unique(v.begin(), v.end()), v.end());

typedef long long LL;
template<typename T> using V = std::vector<T>;
template<typename T> using VV = std::vector<std::vector<T>>;
template<typename T> using VVV = std::vector<std::vector<std::vector<T>>>;

template<class T> inline T ceil(T a, T b) { return (a + b - 1) / b; }
template<class T> inline void print(T x) { std::cout << x << std::endl; }
template<class T> inline void print_vec(const std::vector<T> &v) { for (int i = 0; i < v.size(); ++i) {  if (i != 0) {std::cout << " ";} std::cout << v[i];} std::cout << "\n"; }
template<class T> inline bool inside(T y, T x, T H, T W) {return 0 <= y and y < H and 0 <= x and x < W; }
template<class T> inline double euclidean_distance(T y1, T x1, T y2, T x2) { return sqrt((x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2)); }
template<class T> inline double manhattan_distance(T y1, T x1, T y2, T x2) { return abs(x1 - x2) + abs(y1 - y2); }

const int INF = 1L << 30;
const double EPS = 1e-9;
const std::string YES = "YES", Yes = "Yes", NO = "NO", No = "No";
const std::vector<int> dy4 = { 0, 1, 0, -1 }, dx4 = { 1, 0, -1, 0 };    // 4近傍（右, 下, 左, 上）
const std::vector<int> dy8 = { 0, -1, 0, 1, 1, -1, -1, 1 }, dx8 = { 1, 0, -1, 0, 1, 1, -1, -1 };

using namespace std;

// 最大流問題を解く O(|E||V|^2)
class Dinic {

public:
    struct Edge {
        const int to;         // 行き先のノードid
        long long flow;       // 流量
        const long long cap;  // 容量
        const int rev;        // 逆辺のノードid
        const bool is_rev;    // 逆辺かどうか
        Edge(int to, long long flow, long long cap, int rev, bool is_rev) : to(to), flow(flow), cap(cap), rev(rev), is_rev(is_rev) {
            assert(this->cap >= 0);
        }
    };

    vector<vector<Edge>> graph; // グラフの隣接リスト表現
    vector<int> level;          // sからの距離
    vector<unsigned int> iter;  // どこまで調べ終わったか

    explicit Dinic(unsigned int num_of_node) {
        assert(num_of_node > 0);
        graph.resize(num_of_node);
        level.resize(num_of_node);
        iter.resize(num_of_node);

    }

    // fromからtoへ向かう容量capの辺をグラフに追加する
    void add_edge(unsigned int from, unsigned int to, long long cap) {
        graph[from].emplace_back(Edge(to, 0, cap, (unsigned int)graph[to].size(), false));
        graph[to].emplace_back(Edge(from, cap, cap, (unsigned int)graph[from].size() - 1, true));
    }

    // sからtへの最大流を求める
    long long max_flow(unsigned int s, unsigned int t) {
        long long flow = 0;
        while (true) {
            bfs(s);
            if (level.at(t) < 0) {
                return flow;
            }
            fill(iter.begin(), iter.end(), 0);
            long long f;
            while ((f = dfs(s, t, INT_MAX)) > 0) {
                flow += f;
            }
        }
    }

private:
    // sからの最短距離をBFSで計算する
    void bfs(unsigned int s) {
        fill(level.begin(), level.end(), -1);
        queue<unsigned int> que;
        level.at(s) = 0;
        que.push(s);
        while (not que.empty()) {
            unsigned int v = que.front();
            que.pop();
            for (int i = 0; i < graph.at(v).size(); ++i) {
                Edge &e = graph.at(v).at(i);
                if ((e.cap - e.flow) > 0 and level.at(e.to) < 0) {
                    level.at(e.to) = level.at(v) + 1;
                    que.push(e.to);
                }
            }
        }
    }

    // 増加パスをDFSで探す
    long long dfs(unsigned int v, unsigned int t, long long f) {
        if (v == t) {
            return f;
        }
        for (unsigned int &i = iter.at(v); i < graph.at(v).size(); ++i) {
            Edge &e = graph.at(v).at(i);
            if ((e.cap - e.flow) > 0 and level.at(v) < level.at(e.to)) {
                long long d = dfs(e.to, t, min(f, e.cap - e.flow));
                if (d > 0) {
                    e.flow += d;
                    graph.at(e.to).at(e.rev).flow -= d;
                    return d;
                }
            }
        }
        return 0;
    }
};

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    int N;
    cin >> N;

    vector<pair<int, int>> red, blue;
    FOR(i, 0, N) {
        int a, b;
        cin >> a >> b;
        red.emplace_back(make_pair(a, b));
    }
    FOR(i, 0, N) {
        int c, d;
        cin >> c >> d;
        blue.emplace_back(make_pair(c, d));
    }

    Dinic dinic(N * 2 + 2);
    int source = N * 2;
    int sink = source + 1;

    FOR(i, 0, N) {
        auto r = red[i];
        FOR(j, 0, N) {
            auto b = blue[j];

            if (r.first < b.first and r.second < b.second) {
                dinic.add_edge(i, N + j, 1);
            }
        }
    }

    FOR(i, 0, N) {
        dinic.add_edge(source, i, 1);
    }
    FOR(i, 0, N) {
        dinic.add_edge(N + i, sink, 1);
    }

    print(dinic.max_flow(source, sink));


    return 0;
}

Measured memory_bytes: 512