#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, m, a[3001], b[3001], i, j, ans = 0;
  cin >> n >> m;
  for (i = 0; i < n; i++) cin >> a[i];
  for (i = 0; i < m; i++) cin >> b[i];
  sort(a, a + n);
  sort(b, b + m);
  i = n - 1;
  j = m - 1;
  while (i >= 0) {
    if (j < 0) {
      ans += i + 1;
      break;
    }
    if (b[j] >= a[i]) {
      i--;
      j--;
    } else if (b[j] < a[i]) {
      ans++;
      i--;
    }
  }
  cout << ans << endl;
  return 0;
}
