#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, m;
  cin >> n >> m;
  std::vector<int> a, b;
  for (int i = 0; i < n; ++i) {
    int temp;
    cin >> temp;
    a.push_back(temp);
  }
  for (int i = 0; i < m; ++i) {
    int temp;
    cin >> temp;
    b.push_back(temp);
  }
  sort(a.begin(), a.end());
  sort(b.begin(), b.end());
  int count = 0;
  bool flag = 0;
  for (int i = 0; i < a.size(); i += 1) {
    flag = 0;
    for (int j = i; j < b.size(); j += 1) {
      if (b[j] >= a[i]) {
        flag = 1;
        b[j] = 0;
        break;
      } else
        continue;
    }
    if (!flag) count += 1;
  }
  cout << count << endl;
  return 0;
}
