#include <stdio.h>
 
int main() {
  int n, s[100000], q, t[50000], i, left, right, mid, count = 0;
 
  scanf("%d", &n);
  for(i = 0; i < n; i++)
    scanf("%d", &s[i]);
 
  scanf("%d", &q);
  for(i = 0; i < q; i++)
    scanf("%d", &t[i]);
 
  for(i = 0; i < q; i++){
    left = 0;
    right = n;
 
    while(left < right){
      mid = (left + right)/2;
 
      if(s[mid] == t[i]){
    count++;
    break;
      }
 
      else if(s[mid] < t[i])
    left = mid + 1;
      else
    right = mid;
    }
 
  }
 
  printf("%d\n", count);
  return 0;
}