#include <bits/stdc++.h>
#define _GLIBCXX_DEBUG
using namespace std;
using ll = long long;
using vec = vector<ll>;
using vect = vector<double>;
using Graph = vector<vector<ll>>;
#define loop(i, n) for (ll i = 0; i < n; i++)
#define Loop(i, m, n) for (ll i = m; i < n; i++)
#define pool(i, n) for (ll i = n; i >= 0; i--)
#define Pool(i, m, n) for (ll i = n; i >= m; i--)
#define mod 1000000007ll
#define setbit bitset<8>
#define flagcount __builtin_popcount
#define flag(x) (1 << x)
#define flagadd(bit, x) bit |= flag(x)
#define flagpop(bit, x) bit &= ~flag(x)
#define flagon(bit, i) bit &flag(i)
#define flagoff(bit, i) !(bit & (1 << i))
#define all(v) v.begin(), v.end()
#define low2way(v, x) lower_bound(all(v), x)
#define high2way(v, x) upper_bound(all(v), x)
#define count2way(v, x) high2way(v, x) - low2way(v, x)
#define lower(v, x) low2way(v, x) - v.begin()       //1番左が0、もし見つから無いならｎを出力
#define higher(v, x) high2way(v, x) - v.begin() - 1 //1番左が0、もし見つからないならn-1を出力（注意）
#define putout(a) cout << a << endl
#define putout2(a, b) \
    putout(a);        \
    putout(b)
#define putout3(a, b, c) \
    putout(a);           \
    putout(b);           \
    putout(c)
#define putout4(a, b, c, d) \
    putout(a);              \
    putout(b);              \
    putout(c);              \
    putout(d)
#define putout5(a, b, c, d, e) \
    putout(a);                 \
    putout(b);                 \
    putout(c);                 \
    putout(d);                 \
    putout(e)
#define Gput(a, b) G[a].push_back(b)
#define cin1(a) cin >> a
#define cin2(a, b) cin >> a >> b
#define cin3(a, b, c) cin >> a >> b >> c
#define cin4(a, b, c, d) cin >> a >> b >> c >> d
#define cin5(a, b, c, d, e) cin >> a >> b >> c >> d >> e
#define sum(v) accumulate(all(v), 0ll)
#define gcd(x, y) __gcd(x, y)
ll ctoi(char c)
{
    if (c >= '0' && c <= '9')
    {
        return c - '0';
    }
    return 0;
}
template <typename T>
T lcm(T x, T y)
{
    T z = gcd(x, y);
    return x * y / z;
}
template <typename T>
bool primejudge(T n)
{
    if (n < 2)
        return false;
    else if (n == 2)
        return true;
    else if (n % 2 == 0)
        return false;
    double sqrtn = sqrt(n);
    for (T i = 3; i < sqrtn + 1; i++)
    {
        if (n % i == 0)
        {
            return false;
        }
        i++;
    }
    return true;
}
template <typename T>
T modinv(T a, T m)
{
    T b = m, u = 1, v = 0;
    while (b)
    {
        T t = a / b;
        a -= t * b;
        swap(a, b);
        u -= t * v;
        swap(u, v);
    }
    u %= m;
    if (u < 0)
        u += m;
    return u;
}
//場合によって使い分ける
//const ll dx[4]={1,0,-1,0};
//const ll dy[4]={0,1,0,-1};
const ll dx[8] = {1, 1, 0, -1, -1, -1, 0, 1};
const ll dy[8] = {0, 1, 1, 1, 0, -1, -1, -1};
//多次元配列の宣言法
//vector<vector<ll>> field(h, vector<ll>(w));
template <class T>
inline void chmax(T &a, T b)
{
    if (a < b)
        a = b;
}
template <class T>
inline void chmin(T &a, T b)
{
    if (a > b)
        a = b;
}
/*
ライブラリをここに置いてコメントを削除
*/
#define fst first
#define snd second
const long long INF = (1ll << 50);
struct graph
{
    typedef long long flow_type;
    struct edge
    {
        int src, dst;
        flow_type capacity, flow;
        size_t rev;
    };
    int n;
    vector<vector<edge>> adj;
    graph(int n) : n(n), adj(n) {}
    void add_edge(int src, int dst, flow_type capacity)
    {
        adj[src].push_back({src, dst, capacity, 0, adj[dst].size()});
        adj[dst].push_back({dst, src, 0, 0, adj[src].size() - 1});
    }
    flow_type max_flow(int s, int t)
    {
        vector<int> level(n), iter(n);
        function<int(void)> levelize = [&]() { // foward levelize
            level.assign(n, -1);
            level[s] = 0;
            queue<int> Q;
            Q.push(s);
            while (!Q.empty())
            {
                int u = Q.front();
                Q.pop();
                if (u == t)
                    break;
                for (auto &e : adj[u])
                {
                    if (e.capacity > e.flow && level[e.dst] < 0)
                    {
                        Q.push(e.dst);
                        level[e.dst] = level[u] + 1;
                    }
                }
            }
            return level[t];
        };
        function<flow_type(int, flow_type)> augment = [&](int u, flow_type cur) {
            if (u == t)
                return cur;
            for (int &i = iter[u]; i < adj[u].size(); ++i)
            {
                edge &e = adj[u][i], &r = adj[e.dst][e.rev];
                if (e.capacity > e.flow && level[u] < level[e.dst])
                {
                    flow_type f = augment(e.dst, min(cur, e.capacity - e.flow));
                    if (f > 0)
                    {
                        e.flow += f;
                        r.flow -= f;
                        return f;
                    }
                }
            }
            return flow_type(0);
        };
        for (int u = 0; u < n; ++u) // initialize
            for (auto &e : adj[u])
                e.flow = 0;

        flow_type flow = 0;
        while (levelize() >= 0)
        {
            fill(all(iter), 0);
            for (flow_type f; (f = augment(s, INF)) > 0;)
                flow += f;
        }
        return flow;
    }
};
/*
    graph g(n);
    //g.add_edge(u, v, w);
    g.add_edge(u-1, v-1, w);//容量wの有向辺
    g.max_flow(0, n-1)
*/
int main()
{
    cout << fixed << setprecision(30);
    ll n;
    cin >> n;
    graph g(2 * n + 2);
    vec a(n), b(n), c(n), d(n);
    loop(i, n) cin >> a[i] >> b[i];
    loop(i, n) cin >> c[i] >> d[i];
    loop(i, n)
    {
        g.add_edge(0, 1 + i, 1);
        g.add_edge(n + 1 + i, 2 * n + 1, 1);
    }
    loop(i, n)
    {
        loop(j, n)
        {
            if (a[i] < c[j] && b[i] < d[j])
                g.add_edge(1 + i, n + 1 + j, 1);
        }
    }
    putout(g.max_flow(0, 2 * n + 1));
    return 0;
}


Measured memory_bytes: 512