#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b;
  cin >> a >> b;
  vector<int> arr1, arr2;
  while (a--) {
    int value;
    cin >> value;
    arr1.push_back(value);
  }
  while (b--) {
    int value;
    cin >> value;
    arr2.push_back(value);
  }
  int p1 = 0, p2 = 0;
  sort(arr1.begin(), arr1.end());
  sort(arr2.begin(), arr2.end());
  while (p1 < arr1.size() && p2 < arr2.size()) {
    if (arr1[p1] == arr2[p2])
      p1++, p2++;
    else if (arr1[p1] > arr2[p2]) {
      p2++;
    } else {
      p1++, p2++;
    }
  }
  int left = arr1.size() - p1;
  cout << left;
}
