#include <bits/stdc++.h>
using namespace std;
typedef long long LL;
// chmax, chmin
template <class T>
inline bool chmax(T& a, T b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T>
inline bool chmin(T& a, T b) {
  if (a > b) {
    a = b;
    return 1;
  }
  return 0;
}

template <typename T>
function<T(T, T)> op_max = [](T a, T b) -> T { return max(a, b); };
template <typename T>
function<T(T, T)> op_min = [](T a, T b) -> T { return min(a, b); };

template <typename T>
function<T(T, T)> op_sum = [](T a, T b) -> T { return a + b; };

namespace detail {
template <typename T, std::size_t NDIMS>
struct vector_builder {
  using type = std::vector<typename vector_builder<T, NDIMS - 1>::type>;

  static type make(std::vector<std::size_t> dims, const T& v = {}) {
    const auto vec = std::vector<T>(dims.empty() ? 0 : dims.back(), v);
    if (!dims.empty()) dims.pop_back();
    return vector_builder<std::vector<T>, NDIMS - 1>::make(dims, vec);
  }
};

template <typename T>
struct vector_builder<T, 1> {
  using type = std::vector<T>;

  static type make(std::vector<std::size_t> dims, const T& v = {}) {
    return type(dims.empty() ? 0 : dims.back(), v);
  }
};
}  // namespace detail

template <typename T, typename... SIZE_T>
auto exvector(const T& v, SIZE_T... dims) {
  static_assert(sizeof...(dims) != 0, "invalid dimension");
  std::vector<std::size_t> vec_dims{dims...};
  return detail::vector_builder<T, sizeof...(dims)>::make(vec_dims, v);
}

using namespace std;
//********************  dumps ************************//

template <typename T>
void dump(const T& data, vector<int>& iter) {
  cout << data << " ";
}
template <typename T>
void dump(const vector<T>& data, vector<int>& iter) {
  for (auto elem : data) dump(elem, iter);
  cout << endl;
}

template <typename T>
void dump(const vector<vector<T>>& data, vector<int>& iter) {
  for (auto elem : iter) {
    cout << "[" << elem << "]";
  }
  cout << endl;
  for (int i = 0; i < data.size(); i++) {
    iter.push_back(i);
    dump(data[i], iter);
    iter.pop_back();
  }
  cout << endl;
}

template <typename T>
void dump(const vector<T>& data, int dummy) {
  for (int i = 0; i < data.size(); i++) {
    cout << "[" << i << "] " << data[i] << endl;
  }
}
template <typename T>
void dump(const T& data) {  // T : data, U = base type val.
  vector<int> iter;
  dump(data, iter);
}

struct Data2D {
  LL x;
  LL y;
  LL demand;

  Data2D(LL x, LL y, LL demand) : x(x), y(y), demand(demand){};
  bool operator<(Data2D& o) {
    if (x < o.x) return true;
    if (x > o.x) return false;
    if (y > o.y) return true;
    if (y < o.y) return false;
    if (demand < o.demand) return true;
    if (demand > o.demand) return false;
    return false;
  }
};

LL flow2D(vector<Data2D> pts) {
  sort(pts.begin(), pts.end());
  map<LL, LL> mp;
  LL ans = 0;
  for (auto pt : pts) {
    LL y = pt.y;
    LL demand = pt.demand;
    while (demand > 0) {
      auto it = mp.lower_bound(y);
      if (it == mp.end()) break;
      if (it->second <= demand) {
        ans += it->second;
        demand -= it->second;
        mp.erase(it);
      } else {
        it->second -= demand;
        ans += demand;
        demand = 0;
      }
    }
    if (demand < 0) {
      mp[y] -= demand;
    }
  }
  return ans;
}

int main() {
  int N;
  cin >> N;

  vector<Data2D> pts;
  for (int i = 0; i < N; i++) {
    LL a, b;
    cin >> a >> b;
    pts.push_back(Data2D(a, -b, -1));
  }
  for (int i = 0; i < N; i++) {
    LL a, b;
    cin >> a >> b;
    pts.push_back(Data2D(a, -b, 1));
  }
  cout << flow2D(pts) << endl;

  return 0;
}


Measured memory_bytes: 256