#include <bits/stdc++.h>
using namespace std;
int main() {
  int req[3001], pre[3001];
  int n, m, sum;
  cin >> n >> m;
  sum = n;
  for (int i = 0; i < n; i++) {
    cin >> req[i];
  }
  for (int i = 0; i < m; i++) {
    cin >> pre[i];
  }
  sort(pre, pre + m);
  sort(req, req + n);
  int i = 0, j = 0;
  while (i < n && j < m) {
    if (pre[j] >= req[i]) i++, sum--;
    j++;
  }
  cout << sum << endl;
  return 0;
}
