#include <algorithm>
#include <cassert>
#include <iostream>
#include <tuple>
#include <vector>
using namespace std;
struct P {
  int x, y;
};
bool operator<(const P& l, const P& r) { return tie(l.x, l.y) < tie(r.x, r.y); }
int main() {
  int n, b;
  cin >> n >> b;
  vector<P> ps(n);  // CCW order
  for (auto& p : ps) cin >> p.x >> p.y;
  vector<int> bs(b);
  for (auto& b : bs) cin >> b;
  bs.push_back(1e9);
  sort(bs.begin(), bs.end());
  auto bi = bs.begin();
  int ans = 0, pending = 0, ok = 1;
  auto pi = min_element(ps.begin(), ps.end());  // lowest leftmost point
  for (; *bi < pi->x; ++bi) ++ans;              // points before left
  while (true) {
    auto pj = next(pi);
    if (pj == ps.end()) pj = ps.begin();
    if (pj->x < pi->x) break;
    int c = 0;
    for (; *bi < pj->x; ++bi) ++c;  // number of points on this segment
    if (pj->y < pi->y) {
      if (ok) {
        ans += c;
      } else
        pending = 0;
    } else if (pj->y == pi->y) {
      if (pj->y > 0) {
        ans += c;
      } else
        pending = 0;
    } else if (pj->y > pi->y) {
      if (pj->y > 0)
        ans += c;
      else
        pending += c;
    } else
      assert(false);
    pi = pj;
  }
  for (; *bi < 1e9; ++bi) ++ans;  // points after right
  cout << (b - ans) << endl;
}