#include <bits/stdc++.h>
using namespace std;
#ifdef _DEBUG
#define _GLIBCXX_DEBUG
#include "dump.hpp"
#else
#define dump(...)
#endif
 
#define int long long
// typedef __int128_t Int;
#define DBG 1
#define rep(i, a, b) for (int i = (a); i < (b); i++)
#define rrep(i, a, b) for (int i = (b)-1; i >= (a); i--)
#define loop(n) rep(loop, (0), (n))
#define all(c) begin(c), end(c)
const int INF =
    sizeof(int) == sizeof(long long) ? 0x3f3f3f3f3f3f3f3fLL : 0x3f3f3f3f;
    const int MOD = (int)(1e9) + 7;
    const double PI = acos(-1);
    const double EPS = 1e-9;
    template <class T> bool chmax(T &a, const T &b) {
          if (a < b) {
                  a = b;
                      return true;
                        }
            return false;
    }
template <class T> bool chmin(T &a, const T &b) {
      if (a > b) {
              a = b;
                  return true;
                    }
        return false;
}

struct Edge {
      int from, to, cost, rev;
        Edge(int from, int to, int cost, int rev)
                  : from(from), to(to), cost(cost), rev(rev) {}
};
struct Graph {
      int V;
        vector<vector<Edge>> G;
          vector<int> used;
            Graph(int V) : V(V) {
                    used = vector<int>(V, 0);
                        G = vector<vector<Edge>>(V);
                          }
              void add_edge(int from, int to, int cost = 1) {
                      G[from].push_back(Edge(from, to, cost, G[to].size()));
                          G[to].push_back(Edge(to, from, 0, G[from].size() - 1));
                            }
                int augment_path(int s, int t, int f) {
                        if (s == t)
                                  return f;
                            used[s] = true;
                                rep(i, 0, G[s].size()) {
                                          Edge &e = G[s][i];
                                                if (!used[e.to] && e.cost > 0) {
                                                            int d = augment_path(e.to, t, min(f, e.cost));
                                                                    if (d > 0) {
                                                                                  e.cost -= d;
                                                                                            G[e.to][e.rev].cost += d;
                                                                                                      return d;
                                                                                                              }
                                                                          }
                                                    }
                                    return 0;
                                      }
                  int max_flow(int s, int t) {
                          int flow = 0;
                              while (1) {
                                        used = vector<int>(V, 0);
                                              int f = augment_path(s, t, INF);
                                                    if (f == 0)
                                                                break;
                                                          flow += f;
                                                              }
                                  return flow;
                                    }
}
;



signed main() {
      cin.tie(0);
      ios::sync_with_stdio(false);
      cout << fixed << setprecision(12);

      int N;cin>>N;
      Graph g(2*N+2);
      int s=2*N,t=s+1;
      vector<int>a(N),b(N),c(N),d(N);
      rep(i,0,N)cin>>a[i]>>b[i];
      rep(i,0,N)cin>>c[i]>>d[i];
      rep(i,0,N)rep(j,0,N){
          if(a[i]<c[j] and b[i]<d[j]){
              //cout<< i<< " "<<j<<endl;
              g.add_edge(i,N+j);
          }
      }
      rep(i,0,N)g.add_edge(s,i);
      rep(j,0,N)g.add_edge(N+j,t);
      cout<<g.max_flow(s,t)<<endl;

      
      return 0;
}


Measured memory_bytes: 512