#include <bits/stdc++.h>
using namespace std;
int a1[5000];
int a2[5000];
int main() {
  int i, j, m, n, now, ans;
  scanf("%d%d", &n, &m);
  for (i = 0; i < n; i++) scanf("%d", &a1[i]);
  sort(a1, a1 + n);
  for (i = 0; i < m; i++) scanf("%d", &a2[i]);
  sort(a2, a2 + m);
  now = 0;
  ans = n;
  for (i = 0; i < n; i++) {
    while ((now < m) && (a2[now] < a1[i])) now++;
    if (now < m)
      ans--;
    else
      break;
    now++;
  }
  printf("%d\n", ans);
  return 0;
}
