#include <bits/stdc++.h>
inline int gcd(int a, int b) {
  while (b) b ^= a ^= b ^= a %= b;
  return a;
}
using namespace std;
int main() {
  int n, m;
  int a[3001], b[3001];
  scanf("%d%d", &n, &m);
  for (int i = (0); i < (n); i++) scanf("%d", &a[i]);
  for (int i = (0); i < (m); i++) scanf("%d", &b[i]);
  sort(a, a + n);
  sort(b, b + m);
  int ptr1 = 0, ptr2 = 0;
  while (ptr1 < n && ptr2 < m) {
    if (a[ptr1] <= b[ptr2]) {
      ptr1++;
      ptr2++;
    } else
      ptr2++;
  }
  int ans = 0;
  if (ptr1 != n) {
    ans += n - ptr1;
  }
  printf("%d\n", ans);
  return 0;
}
