#include <bits/stdc++.h>
using namespace std;
int a[100], b[100];
int main() {
  int n, m, i, j, num, temp, maxn;
  scanf("%d", &n);
  for (i = 0; i < n; i++) scanf("%d", &a[i]);
  scanf("%d", &m);
  for (i = 0; i < m; i++) scanf("%d", &b[i]);
  num = temp = maxn = 0;
  for (i = 0; i < n; i++)
    for (j = 0; j < m; j++) {
      if (b[j] % a[i] == 0) {
        temp = b[j] / a[i];
        if (temp > maxn) {
          num = 1;
          maxn = temp;
        } else if (temp == maxn)
          num++;
      }
    }
  printf("%d\n", num);
}
