#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;

typedef int _loop_int;
#define REP(i,n) for(_loop_int i=0;i<(_loop_int)(n);++i)
#define FOR(i,a,b) for(_loop_int i=(_loop_int)(a);i<(_loop_int)(b);++i)
#define FORR(i,a,b) for(_loop_int i=(_loop_int)(b)-1;i>=(_loop_int)(a);--i)

#define DEBUG(x) cout<<#x<<": "<<x<<endl
#define DEBUG_VEC(v) cout<<#v<<":";REP(i,v.size())cout<<" "<<v[i];cout<<endl
#define ALL(a) (a).begin(),(a).end()

#define CHMIN(a,b) a=min((a),(b))
#define CHMAX(a,b) a=max((a),(b))

// mod
const ll MOD = 1000000007ll;
#define FIX(a) ((a)%MOD+MOD)%MOD

// floating
typedef double Real;
const Real EPS = 1e-11;
#define EQ0(x) (abs(x)<EPS)
#define EQ(a,b) (abs(a-b)<EPS)
typedef complex<Real> P;

static const ll INF = 1000000000000000ll;

#define MAX_V 1000
// Dinic http://www.prefield.com/algorithm/graph/dinic.html
struct dinic{
  struct edge{int to;ll cost;};
  int n;
  vector< vector<edge> > G;
  vector<vl> flow, capacity;
#define RESIDUE(s,t) (capacity[s][t]-flow[s][t])
  vi level;
  vector<bool> finished;
  dinic(int _n){
    n = _n;
    G.assign(n,vector<edge>());
    flow.assign(n,vl(n,0));
    capacity.assign(n,vl(n,0));
    level.assign(n,0);
    finished.assign(n,false);
  }
  void add_edge(int from,int to,ll cost){
    assert(0<=from && from<n);
    assert(0<=to && to<n);
    G[from].push_back((edge){to,cost});
    G[to].push_back((edge){from,0ll});  // 逆に流すフローのためのダミー辺
  }
  ll dfs(int u, int t, ll cur){
    if(u==t || cur==0) return cur;
    if(finished[u]) return 0;
    finished[u] = true;
    REP(i,G[u].size()){
      edge e = G[u][i];
      if(level[e.to] > level[u]){
        ll f = dfs(e.to, t, min(cur, RESIDUE(u,e.to)));
        if(f>0){
          flow[u][e.to] += f;
          flow[e.to][u] -= f;
          finished[u] = false;
          return f;
        }
      }
    }
    return 0;
  }
  ll calc(int s, int t){
    REP(i,n)REP(j,n)flow[i][j]=capacity[i][j]=0;
    REP(u,n)REP(j,G[u].size()){
      edge e = G[u][j];
      capacity[u][e.to] += e.cost;
    }
    ll total = 0;
    while(true){
      REP(i,n)level[i] = -1;
      level[s] = 0;
      queue<int> Q; Q.push(s);
      int d = n;
      while(!Q.empty()){
        int u = Q.front(); Q.pop();
        REP(i,G[u].size()){
          edge e = G[u][i];
          if(RESIDUE(u,e.to) > 0 && level[e.to] == -1){
            Q.push(e.to);
            level[e.to] = level[u] + 1;
          }
        }
      }
      REP(i,n)finished[i]=false;
      bool flag = false;
      while(true){
        ll f = dfs(s,t,INF);
        if(f==0)break;
        total += f;
        flag = true;
      }
      if(!flag)break;
    }
    return total;
  }
};

int n;
pii red[125], blue[125];

int main(){
  scanf("%d",&n);
  REP(i,n){
    int x,y;
    scanf("%d%d",&x,&y);
    red[i] = pii(x,y);
  }
  REP(i,n){
    int x,y;
    scanf("%d%d",&x,&y);
    blue[i] = pii(x,y);
  }
  dinic D(2*n+2);
  REP(i,n)D.add_edge(2*n, i, 1);
  REP(i,n)D.add_edge(n+i, 2*n+1, 1);
  REP(i,n)REP(j,n)if(red[i].first < blue[j].first && red[i].second < blue[j].second){
    D.add_edge(i, n+j, 1);
  }
  int ans = D.calc(2*n, 2*n+1);
  printf("%d\n",ans);
  return 0;
}


Measured memory_bytes: 1024