//Create Time: 2018-04-27 15:57:19
#include <iostream>
#include <cstdio>
#include <cstring>
#include <string>
#include <cmath>
#include <algorithm>
#include <vector>
#include <cstdlib>
#include <sstream>
#include <fstream>
#include <functional>
#include <list>
#include <deque>
#include <queue>
#include <stack>
#include <map>
#include <set>
#include <bitset>
#include <cctype>
#include <ctime>
#include <utility>
#include <complex>
#include <cassert>
#include <climits>
#include <iterator>
#include <tuple>
using namespace std;
#define snuke(i,x) for (__typeof((x).begin()) i = (x).begin(); i != (x).end(); ++i)
#define rep(i,a,n) for (int i=(a);i<(n);i++)
#define per(i,n,a) for (int i=(n)-1;i>=(a);i--)
// #define OUT(x) std::cout<<(#x)<<":"<<(x)<<std::endl
// #define TST(x) std::cout<<(#x)<<":"<<(x)<<" "
#define OUT(args...) {string _s=#args;replace(_s.begin(),_s.end(),',',' ');stringstream _ss(_s);istream_iterator<string> _it(_ss);OUT_TST("\n",_it,args);}
#define TST(args...) {string _s=#args;replace(_s.begin(),_s.end(),',',' ');stringstream _ss(_s);istream_iterator<string> _it(_ss);OUT_TST("",_it,args);}
#define SZ(v) ((int)(v).size())
#define all(v) (v).begin(), (v).end()
#define unq(x) sort(all(x)),(x).erase(unique(all(x)),(x).end())
#define mem(f,x) memset((f), (x), sizeof(f))
#define clr(f) mem(f,0)
#define x first
#define y second
#define mp make_pair
#define pb push_back
#define mt make_tuple
#define eb emplace_back
#define DEBUG
void OUT_TST(string s,istream_iterator<string> it) {cerr<<s;}
template<typename T, typename... Args> void OUT_TST(string s,istream_iterator<string> it,T a,Args... args){cerr<<*it<<"="<<a<<" ";OUT_TST(s,++it,args...);}
template<class T> void rd(T&ret){ret=0;bool ok=0,u=0;for(;;){int c=getchar();if(c>='0'&&c<='9')ret=(ret<<3)+(ret<<1)+c-'0',ok=1;else if(c=='-')u=1;else if(ok){if(u)ret*=-1;return;}}}
long long powmod(long long p,long long n,long long mod){long long ret=1;for(;n;n>>=1){if(n&1)ret=ret*p%mod;p=p*p%mod;}return ret;}
template <class T> bool chmin(T& a, const T &b) {return b < a? a = b, 1: 0;}
template <class T> bool chmax(T& a, const T &b) {return b > a? a = b, 1: 0;}
int gcd(int a,int b){return b?gcd(b,a%b):a;}
typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<pii > vii;
typedef tuple<int,int,int> tp;
/****head****/
const int N=222;
namespace Hungary{
    const int N=::N;
    bool v[N];      //visited
    bool is_first_half[N];
    int match[N],n;
    vector<int> *an;   //graph

    bool crosspath(int x){
        for(int i=0;i<an[x].size();++i){
            int p = an[x][i];
            if (!v[p]){
                v[p] = 1;
                if (match[p] == -1 || crosspath(match[p])){
                    match[p] = x; return 1;
                }
            }
        }
        return 0;
    }

    int gao(int _n, vector<int> *_an){
        an = _an; n = _n;
        int ret = 0;
        memset(match, -1, sizeof match);
        for(int i=0;i<n;++i) if(is_first_half[i]){
            memset(v, 0, sizeof v);
            if(crosspath(i)) ++ret;
        }
        return ret;
    }
}
pii an[N],bn[N];
vi eg[N];
void add(int x,int y){
    eg[x].pb(y); eg[y].pb(x);
}
int main(){
    int n; scanf("%d",&n);
    rep(i,0,n)scanf("%d%d",&an[i].x,&an[i].y);
    rep(i,0,n)scanf("%d%d",&bn[i].x,&bn[i].y);
    rep(i,0,n)rep(j,0,n){
        if(an[i].x>=bn[j].x || an[i].y>=bn[j].y)continue;
        add(i,j+n);
    }
    memset(Hungary::is_first_half,0,sizeof(Hungary::is_first_half));
    rep(i,0,n)Hungary::is_first_half[i]=1;
    printf("%d\n",Hungary::gao(n<<1,eg));
    return 0;
}


Measured memory_bytes: 256