#include <stdio.h>
#define N 100000
 
int BinarySearch(int, int *, int);
 
int main()
{
  int i, j;
  int n, q;
  int nl[N], s;
  int count = 0;
 
  scanf("%d", &n);
  for(i = 0; i < n; i++)
    {
      scanf("%d", &nl[i]);
    }
 
  scanf("%d", &q);
  for(i = 0; i < q; i++)
    {
      scanf("%d", &s);
      if(BinarySearch(n, nl, s) == 1) 
    {
      count++;
    }
    }
  printf("%d\n", count);
 
  return 0;
}
 
int BinarySearch(int n, int *nl, int s)
{
  int left, mid, right;
 
  left = 0;
  right = n;
  mid = (left + right) / 2;
 
  while(nl[mid] != s)
    {
      if(left + 1 == right) return 0;
      if(nl[mid] < s) left = mid;
      else right = mid;
 
      mid = (left + right) / 2;
    }
 
  return 1;
}