#include <bits/stdc++.h>
using namespace std;
const int N = 100005;
int a[N];
int b[N], bl = 1;
int n;
int ans;
int main() {
  scanf("%d", &n);
  for (int i = 1; i <= n; i++)
    scanf("%d", &a[i]);

  for (int i = 1; i <= n; i++)
    scanf("%d", &b[i]);

  sort(a + 1, a + n + 1);
  sort(b + 1, b + n + 1);

  for (int i = 1; i <= n; i++)
    if (a[i] > b[bl])
      ++ans, ++bl;
  printf("%d\n", ans);
  return 0;
}