#include <bits/stdc++.h>
#define ll long long
#define INF 1000000005
#define MOD 1000000007
#define EPS 1e-10
#define rep(i,n) for(int i=0;i<(int)(n);++i)
#define rrep(i,n) for(int i=(int)(n)-1;i>=0;--i)
#define srep(i,s,t) for(int i=(int)(s);i<(int)(t);++i)
#define each(a,b) for(auto& (a): (b))
#define all(v) (v).begin(),(v).end()
#define len(v) (int)(v).size()
#define zip(v) sort(all(v)),v.erase(unique(all(v)),v.end())
#define cmx(x,y) x=max(x,y)
#define cmn(x,y) x=min(x,y)
#define fi first
#define se second
#define pb push_back
#define show(x) cout<<#x<<" = "<<(x)<<endl
#define spair(p) cout<<#p<<": "<<p.fi<" "<<p.se<<endl
#define sar(a,n) cout<<#a<<":";rep(pachico,n)cout<<" "<<a[pachico];cout<<endl
#define svec(v) cout<<#v<<":";rep(pachico,v.size())cout<<" "<<v[pachico];cout<<endl
#define svecp(v) cout<<#v<<":";each(pachico,v)cout<<" {"<<pachico.first<<":"<<pachico.second<<"}";cout<<endl
#define sset(s) cout<<#s<<":";each(pachico,s)cout<<" "<<pachico;cout<<endl
#define smap(m) cout<<#m<<":";each(pachico,m)cout<<" {"<<pachico.first<<":"<<pachico.second<<"}";cout<<endl

using namespace std;

typedef pair<int,int> P;
typedef pair<ll,ll> pll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<double> vd;
typedef vector<P> vp;
typedef vector<string> vs;

const int MAX_N = 100005;

class BM {
private:
    struct edge {
        int to,cap,rev;
    };
    vector<vector<edge> > G;
    vector<int> level;
    vector<int> iter;
    int U,V;

public:
    BM(int u,int v) {
        U = u,V = v;
        G.resize(U+V+2);
        rep(i,u){
            init_edge(0,i+1);
        }
        rep(i,v){
            init_edge(U+i+1,U+V+1);
        }
    }

    void init_edge(int from,int to) {
        G[from].push_back((edge){to,1,(int)G[to].size()});
    	G[to].push_back((edge){from,0,(int)G[from].size()-1});
    }

    void add_edge(int from,int to) {
        from += 1,to += U+1;
    	G[from].push_back((edge){to,1,(int)G[to].size()});
    	G[to].push_back((edge){from,0,(int)G[from].size()-1});
    }

    void bfs(int s) {
        fill(level.begin(),level.end(),-1);
    	queue<int> que;
    	level[s] = 0;
    	que.push(s);
    	while(!que.empty()){
    		int v = que.front();
    		que.pop();
    		rep(i,(int)G[v].size()){
    			edge &e = G[v][i];
    			if(e.cap > 0 && level[e.to] < 0){
    				level[e.to] = level[v] + 1;
    				que.push(e.to);
    			}
    		}
    	}
    }

    int dfs(int v,int t,int f) {
    	if(v==t){
    		return f;
    	}
    	for(int &i = iter[v];i<(int)G[v].size();i++){
    		edge &e = G[v][i];
    		if(e.cap > 0 && level[v] < level[e.to]){
    			int d = dfs(e.to,t,min(f,e.cap));
    			if(d>0){
    				e.cap -= d;
    				G[e.to][e.rev].cap += d;
    				return d;
    			}
    		}
    	}
    	return 0;
    }

    int solve() {
        level.resize(U+V+2);
        iter.resize(U+V+2);
    	int flow = 0;
        int s=0,t=U+V+1;
    	for(;;){
    		bfs(s);
    		if(level[t]<0){
    			return flow;
    		}
            fill(iter.begin(),iter.end(),0);
    		int f;
    		while((f=dfs(s,t,numeric_limits<int>::max())) > 0){
    			flow += f;
    		}
    	}
    }
};

int main()
{
	cin.tie(0);
	ios::sync_with_stdio(false);
	int n;
	cin >> n;
	vi a(n),b(n),c(n),d(n);
	rep(i,n){
		cin >> a[i] >> b[i];
	}
	rep(i,n){
		cin >> c[i] >> d[i];
	}
	BM bm(n,n);
	rep(i,n){
		rep(j,n){
			if(a[i] < c[j] && b[i] < d[j]){
				bm.add_edge(i,j);
			}
		}
	}
	cout << bm.solve() << "\n";
	return 0;
}

Measured memory_bytes: 384