#include <bits/stdc++.h>
using namespace std;
#define REP(i, s) for (int i = 0; i < s; ++i)
#define ALL(v) (v.begin(), v.end())
#define COUT(x) cout << #x << " = " << (x) << " (L" << __LINE__ << ")" << endl
#define EACH(i, s) for (__typeof__((s).begin()) i = (s).begin(); i != (s).end(); ++i)
 
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
template<class T1, class T2> ostream& operator << (ostream &s, pair<T1,T2> P)
{ return s << '<' << P.first << ", " << P.second << '>'; }
template<class T> ostream& operator << (ostream &s, vector<T> P)
{ for (int i = 0; i < P.size(); ++i) { if (i > 0) { s << " "; } s << P[i]; } return s; }
template<class T> ostream& operator << (ostream &s, vector<vector<T> > P)
{ for (int i = 0; i < P.size(); ++i) { s << endl << P[i]; } return s << endl; }
template<class T> ostream& operator << (ostream &s, set<T> P)
{ EACH(it, P) { s << "<" << *it << "> "; } return s << endl; }
template<class T1, class T2> ostream& operator << (ostream &s, map<T1,T2> P)
{ EACH(it, P) { s << "<" << it->first << "->" << it->second << "> "; } return s << endl; }
 const int MAX_L = 110;
const int MAX_R = 110;
 
struct Graph {
    int L;
    vector<int> list[MAX_L];
    
    void init(int n = 0) { L = n; for (int i = 0; i < MAX_L; ++i) list[i].clear(); }
    inline vector<int>& operator [] (int i) { return list[i]; }
    void addedge(int from, int to) { list[from].push_back(to); }
    friend ostream& operator << (ostream& s, const Graph& G) {
        s << endl; for (int i = 0; i < G.L; ++i) { s << i << " : " << G.list[i] << endl; }return s;
    }
};
 
Graph G;
 
int L = MAX_L;
bool seen[MAX_L];
bool matched[MAX_L];
int level[MAX_L];
int matching[MAX_R];
 
void hobfs(Graph &G) {
    queue<int> que;
    for (int left = 0; left < L; ++left) {
        level[left] = -1;
        if (!matched[left]) {
            que.push(left);
            level[left] = 0;
        }
    }
    level[L] = L;
    while (!que.empty()) {
        int left = que.front();
        que.pop();
        for (int i = 0; i < G[left].size(); ++i) {
            int right = G[left][i];
            int next = matching[right];
            if (level[next] == -1) {
                level[next] = level[left] + 1;
                que.push(next);
            }
        }
    }
}
 
bool hodfs(Graph &G, int left) {
    if (left == L) return true;
    if (seen[left]) return false;
    seen[left] = true;
    for (int i = 0; i < G[left].size(); ++i) {
        int right = G[left][i];
        int next = matching[right];
        if (level[next] > level[left] && hodfs(G, next)) {
            matching[right] = left;
            return true;
        }
    }
    return false;
}
 
int Hopcroft_Karp(Graph &G) {
    L = G.L;
    for (int i = 0; i < MAX_R; ++i) matching[i] = L;
    memset(matched, 0, sizeof(matched));
    
    int res = 0;
    while (true) {
        hobfs(G);
        memset(seen, 0, sizeof(seen));
        bool finished = true;
        for (int left = 0; left < L; ++left) {
            if (!matched[left] && hodfs(G, left)) {
                matched[left] = true;
                ++res;
                finished = false;
            }
        }
        if (finished) break;
    }
    return res;
}
 
 
int N;
int a[110], b[110], c[110], d[110];
 
 
int main() {
    while (cin >> N) {
        for (int i = 0; i < N; ++i) cin >> a[i] >> b[i];
        for (int i = 0; i < N; ++i) cin >> c[i] >> d[i];
        
        G.init(N);
        for (int i = 0; i < N; ++i) {
            for (int j = 0; j < N; ++j) {
                if (a[i] < c[j] && b[i] < d[j]) {
                    G.addedge(i, j);
                }
            }
        }
        
        int res = Hopcroft_Karp(G);
        cout << res << endl;
    }
}

Measured memory_bytes: 256