#include <bits/stdc++.h>
using namespace std;
const int MAXN = 3005;
int arr[MAXN];
int barr[MAXN];
int main() {
  int n, m;
  cin >> n >> m;
  for (int i = 0; i < n; i++) {
    cin >> arr[i];
  }
  for (int j = 0; j < m; j++) {
    cin >> barr[j];
  }
  sort(arr, arr + n);
  sort(barr, barr + m);
  int ans = n;
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < m; j++) {
      if (barr[j] >= arr[i]) {
        barr[j] = -1;
        ans--;
        break;
      }
    }
  }
  cout << ans << " " << '\n';
  return 0;
}
