#include <bits/stdc++.h>
#ifdef __LOCAL
    #define DBG(X) cout << #X << " = " << (X) << endl;
    #define SAY(X) cout << (X) << endl;
#else
    #define DBG(X)
    #define SAY(X)
#endif

#ifdef __LOCAL
    #include <filesystem>
    namespace fs = std::filesystem;
#endif

using namespace std;

using ll = long long int;
using ull = unsigned long long int;
using ld = long double;
using pii = pair<int, int>;
using pll = pair<ll, ll>;

int dx[]={1, 0, -1, 0, 1,-1, 1,-1};
int dy[]={0, 1, 0, -1, 1, 1,-1,-1};
const int INT_INF = (int)(2e9);
const ll  LL_INF = (ll)(2e18);
static mt19937 _g(time(nullptr));
 
inline ll randint(ll a, ll b) { ll w = (_g() << 31LL) ^ _g(); return a + w % (b - a + 1); }
inline void fast_io() { ios_base::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr); };
template<typename T, typename S> inline ostream& operator<<(ostream& os, const pair<T, S> p) { cout << "[" << p.first << ";" << p.second << "]"; return os; }
template<typename T, typename S> inline ostream& operator<<(ostream& os, const map<T, S> p) { for (auto el : p) cout << "[" << el.first << ";" << el.second << "]"; return os; }
template<typename T> inline ostream& operator<<(ostream& os, const vector<T>& v) { for (auto el : v) cout << el << " "; return os; }
template<typename T> inline vector<T> fetch_vec(int sz) { vector<T> ret(sz); for (auto& elem : ret) cin >> elem; return ret; }

struct BipartiteMatching {
  vector< vector< int > > graph;
  vector< int > match, alive, used;
  int timestamp;

  BipartiteMatching(int n) : graph(n), alive(n, 1), used(n, 0), match(n, -1), timestamp(0) {}

  void add_edge(int u, int v) {
    graph[u].push_back(v);
    graph[v].push_back(u);
  }

  bool dfs(int idx) {
    used[idx] = timestamp;
    for(auto &to : graph[idx]) {
      int to_match = match[to];
      if(alive[to] == 0) continue;
      if(to_match == -1 || (used[to_match] != timestamp && dfs(to_match))) {
        match[idx] = to;
        match[to] = idx;
        return true;
      }
    }
    return false;
  }

  int bipartite_matching() {
    int ret = 0;
    for(int i = 0; i < graph.size(); i++) {
      if(alive[i] == 0) continue;
      if(match[i] == -1) {
        ++timestamp;
        ret += dfs(i);
      }
    }
    return ret;
  }

  void output() {
    for(int i = 0; i < graph.size(); i++) {
      if(i < match[i]) {
        cout << i << "-" << match[i] << endl;
      }
    }
  }
};


int N;
vector<pii> R,B;
void input(){
    fast_io();
    #ifdef __LOCAL
        fs::path p = __FILE__;
        fs::path input,output;
        input = output = p.parent_path();
        input += string("/input/") + string(p.stem()) + string(".txt");
        output += string("/output/") + string(p.stem()) + string(".txt");
        freopen(input.c_str(), "r", stdin);
        freopen(output.c_str(), "w", stdout);
    #endif
    cin >> N;
    for (int i = 0; i < N; i++)
    {
        int a,b;
        cin >> a >> b;
        R.emplace_back(a,b);
    }
    for (int i = 0; i < N; i++)
    {
        int a,b;
        cin >> a >> b;
        B.emplace_back(a,b);
    }
}

vector<pii> makeEdges(){
    vector<pii> res;
    for (int i = 0; i < N; i++)
    {
        for (int j = 0; j < N; j++)
        {
            if(R[i].first<=B[j].first && R[i].second<=B[j].second) res.emplace_back(i,N+j);
        }
        
    }    
    return res;
}

int solve(){
    BipartiteMatching bm(2*N);
    auto edges = makeEdges();
    int E=edges.size();
    for(int i = 0; i < E; i++) {
        int a=edges[i].first;
        int b=edges[i].second;
        bm.add_edge(a,b);
    }
    cout << bm.bipartite_matching() << endl;
    return 0;
}   

int main()
{
    input();
    solve();
    return 0;
}


Measured memory_bytes: 384