#include <bits/stdc++.h> // ver2.3.8
#include <boost/math/tools/minima.hpp>
#include <boost/multiprecision/cpp_int.hpp>
#define fmin brent_find_minima
#define int long long
#define endl "\n"
#define ALL(v) (v).begin(),(v).end()
#define COUNT(a,k) upper_bound(ALL(a),k)-lower_bound(ALL(a),k)
#define BIGGER(a,k) a.end()-upper_bound(ALL(a),k)
#define SMALLER(a,k) lower_bound(ALL(a),k)-a.begin()
#define Vi vector<int>
#define VVi vector<Vi>
#define Vs vector<string>
#define Pii pair<int,int>
#define VPii vector<Pii>
#define Tiii tuple<int,int,int>
#define VTiii vector<Tiii>
#define PQi priority_queue<int>
#define PQir priority_queue<int,vector<int>,greater<int>>
#define pb push_back
#define mp make_pair
#define mt make_tuple
#define itos to_string
#define stoi stoll
#define FI first
#define SE second
#define cYES cout<<"YES"<<endl
#define cNO cout<<"NO"<<endl
#define cYes cout<<"Yes"<<endl
#define cNo cout<<"No"<<endl
#define cyes cout<<"yes"<<endl
#define cno cout<<"no"<<endl
#define sortr(v) sort(v,greater<>())
#define rep(i,a,b) for(int i=a;i<b;i++)
#define repeq(i,a,b) for(int i=a;i<=b;i++)
#define repreq(i,a,b) for(int i=a;i>=b;i--)
#define leng(n) (int)(log10(n)+1)
#define dem(a,b) ((a+b-1)/(b))
#define Vin(a) rep(iI,0,a.size())cin>>a[iI]
#define INF 3000000000000000000  //  3.0*10^18(MAXの1/3くらい)
#define MAX LLONG_MAX
#define PI 3.141592653589793238462
#define MOD 1000000007  //  10^9 + 7

using namespace std;
/* fmin(f,L,R,100) で関数の最小値を(x,min)で返す　*/
using boost::math::tools::brent_find_minima;
/* cpp_int (任意の長さのint) */
using boost::multiprecision::cpp_int;

/* デバッグ用 */
void Vout(auto a){if(a.size()==0) cout<<"."<<endl;
else{rep(i,0,a.size()-1)cout<<a[i]<<' ';if(a.size()>0)cout<<a.back()<<endl;}return;}
void Verr(auto a){if(a.size()==0) cerr<<"."<<endl;
else{rep(i,0,a.size()-1)cerr<<a[i]<<' ';if(a.size()>0)cerr<<a.back()<<endl;}return;}
void VVout(auto a){if(a.size()==0)cout<<"."<<endl;
else{rep(i,0,a.size())Vout(a[i]);}return;}
void VVerr(auto a){if(a.size()==0)cerr<<"."<<endl;
else{rep(i,0,a.size())Verr(a[i]);}return;}
void VPout(auto a){if(a.size()==0)cout<<"."<<endl;
else{rep(i,0,a.size())cout<<a[i].FI<<' '<<a[i].SE<<endl;}return;}
void VPerr(auto a){if(a.size()==0)cerr<<"."<<endl;
else{rep(i,0,a.size())cerr<<a[i].FI<<' '<<a[i].SE<<endl;}return;}

/* 便利関数 */
int gcd(int a,int b){return b?gcd(b,a%b):a;} // 最大公約数gcd
int lcm(int a,int b){return a/gcd(a,b)*b;} // 最小公倍数lcm
int mypow(int x, int n, int m){ // 累乗x^n(mod m) O(log(n))
if(n==0)return 1;if(n%2==0)return mypow(x*x%m,n/2,m);else return x*mypow(x,n-1,m)%m;}
int scomb(int n, int r){if((n-r)<r)r=n-r; // nCr(小さい場合)
int a=1;for(int i=n;i>n-r;--i){a=a*i;}for(int i=1;i<r+1;++i){a=a/i;}return a;}
int comb(int n, int r){if((n-r)<r)r=n-r; // nCr(%MOD)
int a=1;for(int i=n;i>n-r;--i){a=a*i%MOD;}for(int i=1;
i<r+1;++i){a=a*mypow(i,MOD-2,MOD)%MOD;}return a%MOD;}
Vi stpowV(){Vi a(100001);
a[0]=1;repeq(i,1,100000)a[i]=a[i-1]*i%MOD;return a;}
//Vi stpow = stpowV();  // 階乗配列(%MOD)
Vi Vsum(Vi &v){Vi S(v.size()+1);rep(i,1,S.size())S[i]+=v[i-1]+S[i-1];return S;}// 累積和
int digit(int k,int i){string s = itos(k);return s[s.size()-i]-'0';} // i桁目の数字
void press(auto &v){v.erase(unique(ALL(v)),v.end());} // 圧縮
Vi zip(Vi b){int Z=b.size(); // 座標圧縮
Pii p[Z+10];int a=b.size();Vi l(a);for(int i=0;i<a;i++)
p[i]=mp(b[i],i);sort(p,p+a);int w=0;for(int i=0;i<a;i++)
{if(i&&p[i].first!=p[i-1].first)w++;l[p[i].second]=w;}return l;}
Vi beki2V(){Vi a(61);int q = 1;rep(i,0,61){a[i]=q;q*=2;}return a;}
//Vi beki2 = beki2V(); // 2^n配列
int modiv(int a,int b){return a*mypow(b,MOD-2,MOD)%MOD;} // a÷b(MOD環境) 



struct edge {
  int to;
  int label;
};

vector<pair<int, int>> gabow_edmonds(const vector<vector<int>>& gra){
  // E0 - 初期化
  int N = gra.size();
  vector<vector<edge>> g(N + 1);
  vector<pair<int, int>> edges;
  {
    int cnt = N + 1;
    for(int i = 0;i < N;i++){
      for(auto to : gra[i]){
        if(i < to){
          g[to + 1].push_back({i + 1, cnt});
          g[i + 1].push_back({to + 1, cnt++});
          edges.push_back({i + 1, to + 1});
        }
      }
    }
  }
  vector<int> mate(N + 1 , 0);
  vector<int> label(N + 1 , -1);
  vector<int> first(N + 1 , 0);
  queue<int> que;

  // firstの遅延評価
  function<int(int)> eval_first = [&](int x){
    if(label[first[x]] < 0) return first[x];
    first[x] = eval_first(first[x]);
    return first[x];
  };

  // サブルーチンR
  function<void(int, int)> rematch = [&](int v, int w){
    // R1
    int t = mate[v];
    mate[v] = w;
    if(mate[t] != v) return;
    // R2
    if(label[v] <= N){
      mate[t] = label[v];
      rematch(label[v] , t);
    }
    // R3
    else{
      int x = edges[label[v] - N - 1].first;
      int y = edges[label[v] - N - 1].second;
      rematch(x , y);
      rematch(y , x);
    }
  };

  function<void(int, int, int)> assignLabel = [&](int x, int y, int num){
    // L0
    int r = eval_first(x);
    int s = eval_first(y);
    int join = 0;
    if(r == s) return;
    // -numがフラグ
    label[r] = -num;
    label[s] = -num;
    while(true){
      // L1
      if(s != 0) swap(r , s);
      // L2
      r = eval_first(label[mate[r]]);
      if(label[r] == -num){
        join = r;
        break;
      }
      label[r] = -num;
    }
    // L3
    int v = first[x];
    // L4
    while(v != join){
      que.push(v);
      label[v] = num;
      first[v] = join;
      v = first[label[mate[v]]];
    }
    // L3
    v = first[y];
    // L4
    while(v != join){
      que.push(v);
      label[v] = num;
      first[v] = join;
      v = first[label[mate[v]]];
    }
    // L5は遅延評価しているため不要
    // L6
    return;
  };

  function<bool(int)> augment_check = [&](int u){
    // E1 後半
    first[u] = 0;
    label[u] = 0;
    que.push(u);
    while(!que.empty()){
      // E2 
      int x = que.front();
      que.pop();
      for(auto e : g[x]){
        int y = e.to;
        // E3
        if(mate[y] == 0 && y != u){
          mate[y] = x;
          rematch(x , y);
          return true;
        }
        // E4
        else if(label[y] >= 0){
          assignLabel(x , y , e.label);
        }
        // E5
        else if(label[mate[y]] < 0){
          label[mate[y]] = x;
          first[mate[y]] = y;
          que.push(mate[y]);
        }
        // E6
      }
    }
    return false;
  };

  for(int i = 1;i <= N;i++){
    // E1
    que = queue<int>();
    if(mate[i] != 0) continue;
    if(augment_check(i)){
      // E7
      fill(label.begin(), label.end(), -1);
    }
  }

  vector<pair<int, int>> ans;
  for(int i = 1;i <= N;i++){
    if(i < mate[i]){
      ans.push_back({i,mate[i]});
    }
  }
  return ans;
}

signed main() {
  cin.tie(0);cout.tie(0);ios::sync_with_stdio(false);cout<<fixed<<setprecision(12);
  int n;
  cin >> n;
  Vi a(n),b(n),c(n),d(n);
  
  rep(i,0,n) cin >> a[i] >> b[i];
  rep(i,0,n) cin >> c[i] >> d[i];
  
  VVi gr(n*2);
  
  rep(i,0,n){
    rep(j,0,n){
      if(a[i] < c[j] && b[i] < d[j]) {
        gr[i].pb(n+j);
        gr[n+j].pb(i);
      }
    }
  }
  VPii memo = gabow_edmonds(gr);
  //VPerr(memo);
  cout << memo.size() << endl;
  return 0;
}

Measured memory_bytes: 512