//
// Created by yamunaku on 2019/11/15.
//

#include <bits/stdc++.h>

using namespace std;

#define rep(i, n) for(int i = 0; i < (n); i++)
#define repl(i, l, r) for(int i = (l); i < (r); i++)
#define per(i, n) for(int i = ((n)-1); i >= 0; i--)
#define perl(i, l, r) for(int i = ((r)-1); i >= (l); i--)
#define all(x) (x).begin(),(x).end()
#define MOD9 998244353
#define MOD1 1000000007
#define IINF 1000000000
#define LINF 1000000000000000000
#define SP <<" "<<
#define CYES cout<<"Yes"<<endl
#define CNO cout<<"No"<<endl
#define CFS cin.tie(0);ios::sync_with_stdio(false)
#define CST(x) cout<<fixed<<setprecision(x)

using ll = long long;
using ld = long double;
using vi = vector<int>;
using mti = vector<vector<int>>;
using vl = vector<ll>;
using mtl = vector<vector<ll>>;
using pi = pair<int, int>;
using pl = pair<ll, ll>;
template<typename T>
using heap = priority_queue<T, vector<T>, function<bool(const T, const T)>>;

template<typename flow_t>
struct Dinic{
    const flow_t INF;

    struct edge{
        int to;
        flow_t cap;
        int rev;
        bool isrev;
        int idx;
    };

    vector<vector<edge> > graph;
    vector<int> min_cost, iter;

    Dinic(int V) : INF(numeric_limits<flow_t>::max()), graph(V){}

    void add_edge(int from, int to, flow_t cap, int idx = -1){
        graph[from].emplace_back((edge) {to, cap, (int) graph[to].size(), false, idx});
        graph[to].emplace_back((edge) {from, 0, (int) graph[from].size() - 1, true, idx});
    }

    bool bfs(int s, int t){
        min_cost.assign(graph.size(), -1);
        queue<int> que;
        min_cost[s] = 0;
        que.push(s);
        while(!que.empty() && min_cost[t] == -1){
            int p = que.front();
            que.pop();
            for(auto &e : graph[p]){
                if(e.cap > 0 && min_cost[e.to] == -1){
                    min_cost[e.to] = min_cost[p] + 1;
                    que.push(e.to);
                }
            }
        }
        return min_cost[t] != -1;
    }

    flow_t dfs(int idx, const int t, flow_t flow){
        if(idx == t) return flow;
        for(int &i = iter[idx]; i < graph[idx].size(); i++){
            edge &e = graph[idx][i];
            if(e.cap > 0 && min_cost[idx] < min_cost[e.to]){
                flow_t d = dfs(e.to, t, min(flow, e.cap));
                if(d > 0){
                    e.cap -= d;
                    graph[e.to][e.rev].cap += d;
                    return d;
                }
            }
        }
        return 0;
    }

    flow_t max_flow(int s, int t){
        flow_t flow = 0;
        while(bfs(s, t)){
            iter.assign(graph.size(), 0);
            flow_t f = 0;
            while((f = dfs(s, t, INF)) > 0) flow += f;
        }
        return flow;
    }

    void output(){
        for(int i = 0; i < graph.size(); i++){
            for(auto &e : graph[i]){
                if(e.isrev) continue;
                auto &rev_e = graph[e.to][e.rev];
                cout << i << "->" << e.to << " (flow: " << rev_e.cap << "/" << e.cap + rev_e.cap << ")" << endl;
            }
        }
    }
};

int main(){
    // CFS;
    int n;
    cin >> n;
    Dinic<int> dc(n + n + 2);
    vector<int> ax(n), ay(n), bx(n), by(n);
    rep(i,n){
        cin >> ax[i] >> ay[i];
    }
    rep(i,n){
        cin >> bx[i] >> by[i];
    }
    rep(i,n){
        rep(j,n){
            if(ax[i] < bx[j] && ay[i] < by[j]){
                dc.add_edge(i, j+n, 1);
            }
        }
    }
    rep(i, n){
        dc.add_edge(n + n, i, 1);
    }
    rep(i, n){
        dc.add_edge(i + n, n + n + 1, 1);
    }
    cout << dc.max_flow(n + n, n + n + 1) << endl;
    return 0;
}

Measured memory_bytes: 384