#include <iostream>
#include <algorithm>
#include <complex>
#include <utility>
#include <vector>
#include <string>
#include <queue>
#include <tuple>
#include <cmath>
#include <bitset>
#include <cctype>
#include <set>
#include <numeric>
#include <functional>
#define _overload3(_1,_2,_3,name,...) name
#define _rep(i,n) repi(i,0,n)
#define repi(i,a,b) for(ll i=ll(a);i<ll(b);++i)
#define rep(...) _overload3(__VA_ARGS__,repi,_rep,)(__VA_ARGS__)
#define all(x) (x).begin(),(x).end()
#define PRINT(V) cout << V << "\n"
#define SORT(V) sort((V).begin(),(V).end())
#define RSORT(V) sort((V).rbegin(), (V).rend())
using namespace std;
using ll = long long;
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }
inline void Yes(bool condition){ if(condition) PRINT("Yes"); else PRINT("No"); }
template<class itr> void cins(itr first,itr last){
    for (auto i = first;i != last;i++){
        cin >> (*i);
    }
}
template<class itr> void array_output(itr start,itr goal){
    string ans = "",k = " ";
    for (auto i = start;i != goal;i++) ans += to_string(*i)+k;
    if (!ans.empty()) ans.pop_back();
    PRINT(ans);
}
ll gcd(ll a, ll b) {
    return a ? gcd(b%a,a) : b;
}
const ll INF = 1e16;
const ll MOD = 1000000007;
typedef pair<ll,ll> P;
const ll MAX = 1005;
constexpr ll nx[4] = {1,0,-1,0};
constexpr ll ny[4] = {0,1,0,-1};
class Ford_Fulkerson{
    private:
        struct edge{
            ll to,cap,rev;
        };
        ll siz;
        vector<vector<edge>> edges;
        vector<bool> done;
    public:
        Ford_Fulkerson(ll n){
            edges.resize(n);
            done.assign(n,0);
            siz = n;
        }
        void add_edge(ll from,ll to,ll cap){
            edges[from].push_back((edge){to,cap,(ll)edges[to].size()});
            edges[to].push_back((edge){from,0,(ll)edges[from].size()-1});
        }
        ll dfs(ll v,ll t,ll f){
            if (v == t) return f;
            done[v] = true;
            for(auto &e:edges[v]){
                if (e.cap > 0 && !done[e.to]){
                    ll d = dfs(e.to,t,min(f,e.cap));
                    if (d > 0){
                        e.cap -= d;
                        edges[e.to][e.rev].cap += d;
                        return d;
                    }
                }
            }
            return 0;
        }
        ll max_flow(ll s,ll t){
            ll flow = 0;
            while(true){
                done.assign(siz,0);
                ll f = dfs(s,t,INF);
                if (f == 0) return flow;
                flow += f;
            }
        }
};

int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);
    ll n;
    cin >> n;
    vector<P> red(n),blue(n);
    Ford_Fulkerson g(2*n+2);
    ll s = 2*n,t = s+1;
    ll a,b,c,d;
    rep(i,n){
        cin >> a >> b;
        red[i] = P(a,b);
    }
    rep(i,n){
        cin >> c >> d;
        blue[i] = P(c,d);
    }
    rep(i,n){
        tie(a,b) = red[i];
        rep(j,n){
            tie(c,d) = blue[j];
            if (a < c && b < d) g.add_edge(i,n+j,1);
        }
    }
    rep(i,n){
        g.add_edge(s,i,1);
        g.add_edge(i+n,t,1);
    }
    PRINT(g.max_flow(s,t));
}


Measured memory_bytes: 512