/* -*- coding: utf-8 -*-
 *
 * 3468.cc:  No.3468 縺ゅｋ繧ｸ繝｣繝・ず繧ｵ繝ｼ繝舌・ - yukicoder
 */

#include<cstdio>
#include<algorithm>

using namespace std;

/* constant */

const int MAX_N = 1000;

/* typedef */

/* global variables */

int ts[MAX_N], ss[MAX_N];

/* subroutines */

/* main */

int main() {
  int n;
  scanf("%d", &n);
  for (int i = 0; i < n; i++) scanf("%d", ts + i);
  for (int i = 0; i < n; i++) scanf("%d", ss + i);

  int cnt = 0, ft = 0;
  for (int i = 0; i < n; i++)
    if (ft <= ss[i]) cnt++, ft = ss[i] + ts[i];

  printf("%d\n", cnt);

  return 0;
}