#include <bits/stdc++.h>
using namespace std;
using namespace std;
template <typename T, typename U>
std::istream& operator>>(std::istream& i, pair<T, U>& p) {
  i >> p.first >> p.second;
  return i;
}
template <typename T>
std::istream& operator>>(std::istream& i, vector<T>& t) {
  for (auto& v : t) {
    i >> v;
  }
  return i;
}
template <typename T, typename U>
std::ostream& operator<<(std::ostream& o, const pair<T, U>& p) {
  o << p.first << ' ' << p.second;
  return o;
}
template <typename T>
std::ostream& operator<<(std::ostream& o, const vector<T>& t) {
  if (t.empty()) o << '\n';
  for (size_t i = 0; i < t.size(); ++i) {
    o << t[i] << " \n"[i == t.size() - 1];
  }
  return o;
}
template <typename T>
using minheap = priority_queue<T, vector<T>, greater<T>>;
template <typename T>
using maxheap = priority_queue<T, vector<T>, less<T>>;
template <typename T>
bool in(T a, T b, T c) {
  return a <= b && b < c;
}
unsigned int logceil(int x) {
  return (unsigned int)(8 * sizeof(int) - __builtin_clz(x));
}
namespace std {
template <typename T, typename U>
struct hash<pair<T, U>> {
  hash<T> t;
  hash<U> u;
  size_t operator()(const pair<T, U>& p) const {
    return t(p.x) ^ (u(p.y) << 7);
  }
};
}  // namespace std
template <typename T>
T gcd(T a, T b) {
  if (a < b) swap(a, b);
  return b ? gcd(b, a % b) : a;
}
template <typename T>
class vector2 : public vector<vector<T>> {
 public:
  vector2() {}
  vector2(size_t a, size_t b, T t = T())
      : vector<vector<T>>(a, vector<T>(b, t)) {}
};
template <typename T>
class vector3 : public vector<vector2<T>> {
 public:
  vector3() {}
  vector3(size_t a, size_t b, size_t c, T t = T())
      : vector<vector2<T>>(a, vector2<T>(b, c, t)) {}
};
template <typename T>
class vector4 : public vector<vector3<T>> {
 public:
  vector4() {}
  vector4(size_t a, size_t b, size_t c, size_t d, T t = T())
      : vector<vector3<T>>(a, vector3<T>(b, c, d, t)) {}
};
template <typename T>
class vector5 : public vector<vector4<T>> {
 public:
  vector5() {}
  vector5(size_t a, size_t b, size_t c, size_t d, size_t e, T t = T())
      : vector<vector4<T>>(a, vector4<T>(b, c, d, e, t)) {}
};
void fastIO() { ios::sync_with_stdio(false); }
class DProzhektori {
 public:
  void solve(std::istream& in, std::ostream& out) {
    int n, m;
    in >> n >> m;
    vector<pair<int, int>> a(n);
    vector<pair<int, int>> bi(m);
    in >> a >> bi;
    map<int, int> b;
    sort(bi.begin(), bi.end());
    for (int i = (0); i < (m); ++i) {
      bool isok = true;
      for (int j = (i + 1); j < (m); ++j)
        if (bi[j].second > bi[i].second) isok = false;
      if (isok) b[bi[i].first] = bi[i].second;
    }
    int ans = 1e7;
    multiset<int> cur;
    set<pair<int, int>> nextd;
    vector<int> curd(n);
    int d = 0;
    for (int i = (0); i < (n); ++i) {
      auto it = b.lower_bound(a[i].first);
      if (it == b.end()) continue;
      if (it->second < a[i].second) continue;
      curd[i] = it->second - a[i].second + 1;
      cur.insert(curd[i]);
      nextd.insert({it->first - a[i].first, i});
    }
    while (!nextd.empty()) {
      ans = min(ans, d + *cur.rbegin());
      auto closest = *nextd.begin();
      nextd.erase(closest);
      auto i = closest.second;
      cur.erase(cur.find(curd[i]));
      d = closest.first + 1;
      auto it = b.lower_bound(a[i].first + d);
      if (it == b.end()) continue;
      if (it->second < a[i].second) continue;
      curd[i] = it->second - a[i].second + 1;
      cur.insert(curd[i]);
      nextd.insert({it->first - a[i].first, i});
    }
    ans = min(ans, d);
    out << ans << endl;
  }
};
int main() {
  DProzhektori solver;
  std::istream& in(std::cin);
  std::ostream& out(std::cout);
  solver.solve(in, out);
  cerr << 1.0 * clock() / CLOCKS_PER_SEC << endl;
  return 0;
}
