#include <bits/stdc++.h>
using namespace std;
int n, m;
int a[3333];
int b[3333];
int main() {
  ios::sync_with_stdio(false);
  cin >> n >> m;
  for (int(i) = (0); (i) < (n); ++(i)) cin >> a[i];
  for (int(i) = (0); (i) < (m); ++(i)) cin >> b[i];
  sort(a, a + n);
  sort(b, b + m);
  int sol = n;
  int cur = 0;
  for (int(i) = (0); (i) < (n); ++(i)) {
    int val = a[i];
    while (cur < m && b[cur] < val) cur++;
    if (cur < m) {
      sol--;
      cur++;
    }
  }
  cout << sol << endl;
  return 0;
}
