#include <bits/stdc++.h>
using namespace std;
const int MOD = 1000000007;
const int MAXN = 4e5;
const int SQRTN = 300;
const int LOGN = 16;
const int INT_INFINITY = 1001001001;
const double EPS = 1e-6;
const int LIMIT = 1e6;
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int n, m, a[3005], b[3005];
  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 i = 0, j = 0, count = 0;
  while (i < n && j < m) {
    if (a[i] <= b[j]) {
      count++;
      i++;
    }
    j++;
  }
  cout << n - count << "\n";
  return 0;
}
