#include <bits/stdc++.h>
using namespace std;
int a[3010], b[3010];
int va[3010], vb[3010];
int main() {
  int n, m;
  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 count = 0;
  for (int i = 0, j = 0; i < n, j < m; i++) {
    for (; j < m; j++) {
      if (b[j] >= a[i] && i < n) {
        ++j;
        ++count;
        break;
      }
    }
  }
  printf("%d\n", n - count);
  return 0;
}
