#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;
}