#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/trie_policy.hpp>
#include <ext/pb_ds/tag_and_trait.hpp>

using namespace std;
using namespace __gnu_pbds;

template<typename T>
using ordered_set = tree<
	T,
	null_type,
	less<T>,
	rb_tree_tag,
	tree_order_statistics_node_update>;

// gives the number of keys with value strictly less than x
#define lesscount(x) order_of_key(x)
// gives the iterator to kth element (starting from 0)
#define kthiterator(x) find_by_order(x)

#define clock_starts() clock_t begin = clock()
#define clock_ends() clock_t end = clock()
#define print_running_time() double elapsed_secs = double(end - begin) / CLOCKS_PER_SEC; \
printf("Elapsed Time : %.10f second(s)\n", elapsed_secs)
#define readfile(s) freopen(s, "r", stdin)
#define writefile(s) freopen(s, "w", stdout)
#define debug(s) cout<< #s <<" = "<< s <<endl
#define all(v) (v).begin(), (v).end()
#define KeepUnique(v) (v).erase( unique(all(v)), v.end() )
#define cin_cout_is_cool ios_base::sync_with_stdio(false); cin.tie(NULL)
#define PrintBinary(n) cout << #n << " = " << bitset<64>(n) << endl
#define MEMSET(a,val) memset(a, val, sizeof a)
#define PB push_back
#define endl '\n'
#define cin(n) scanf("%d", &n)
#define popcount(x) __builtin_popcount((x))
#define popcountll(x) __builtin_popcountll((x))

inline int myrand(int l, int r) {
	int ret = rand(); ret <<= 15; ret ^= rand();
	if(ret < 0) ret = -ret; ret %= (r-l+1); ret += l;
	return ret;
}
template <typename F, typename S>
ostream& operator << (ostream& os, const pair< F, S>& p) {
    return os<<"(" <<p.first<<", "<<p.second<<")"; }

typedef pair<int, int> ii;
template<typename T> using min_pq =
	priority_queue<T, vector<T>, greater<T> >;

template<typename T>T max(T a_,T b_,T c_) { return max(a_,max(b_,c_)); }
template<typename T>T min(T a_,T b_,T c_) { return min(a_,min(b_,c_)); }
template<typename T>T min(T a_,T b_,T c_, T d_) { return min(min(a_, b_),min(c_,d_)); }
template<typename T>T max(T a_,T b_,T c_, T d_) { return max(max(a_, b_),max(c_,d_)); }

//int dx[] = {-1, +0, +1, +0};
//int dy[] = {+0, +1, +0, -1};

template<typename T> inline T ceil(T num, T d)
{ return (T)(num/d) + (num%d>(T)0 ? (T)1 : (T)0); }
#define block_no(idx) 		(idx/BLOCK_SIZE)
#define block_starting(idx) (block_no(idx)*BLOCK_SIZE)
#define block_ending(idx) 	(min(n, block_no(idx)*BLOCK_SIZE+BLOCK_SIZE-1))
#define block_rank(idx) 	(idx%BLOCK_SIZE)

// This code performs maximum bipartite matching.
//
// Running time: O(|E| |V|) -- often much faster in practice
//
//   INPUT: w[i][j] = edge between row node i and column node j
//   OUTPUT: mr[i] = assignment for row node i, -1 if unassigned
//           mc[j] = assignment for column node j, -1 if unassigned
//           function returns number of matches made

typedef vector<int> VI;
typedef vector<VI> VVI;

bool FindMatch(int i, const VVI &w, VI &mr, VI &mc, VI &seen) {
  for (int j = 0; j < w[i].size(); j++) {
    if (w[i][j] && !seen[j]) {
      seen[j] = true;
      if (mc[j] < 0 || FindMatch(mc[j], w, mr, mc, seen)) {
        mr[i] = j;
        mc[j] = i;
        return true;
      }
    }
  }
  return false;
}

int BipartiteMatching(const VVI &w, VI &mr, VI &mc) {
  mr = VI(w.size(), -1);
  mc = VI(w[0].size(), -1);
  
  int ct = 0;
  for (int i = 0; i < w.size(); i++) {
    VI seen(w[0].size());
    if (FindMatch(i, w, mr, mc, seen)) ct++;
  }
  return ct;
}

vector<vector<int> > v;
vector<int> l, r;

int n;
vector<int> a, b, c, d;

int32_t main () {
	//freopen("input.in", "r", stdin);
	//freopen("beetle.out", "w", stdout);
	cin>>n;
	a.assign(n, 0);
	b.assign(n, 0);
	c.assign(n, 0);
	d.assign(n, 0);
	v.assign(n, a);
	for(int i=0; i<n; i++) {
		cin>>a[i]>>b[i];
	}
	for(int i=0; i<n; i++) {
		cin>>c[i]>>d[i];
	}
	for(int i=0; i<n; i++) {
		for(int j=0; j<n; j++) {
			if(a[i] < c[j] and b[i] < d[j]) v[i][j] = 1;
		}
	}
	cout<<BipartiteMatching(v, l, r)<<endl;
	return 0;
}

Measured memory_bytes: 256