#include <stdio.h>

int main()
{
  int n, S[100000], q, T[50000], left, right, mid, i, 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]);
    left = 0;
    right = n;
    while (left < right){
      mid = (left+right)/2;
      if (S[mid] == T[i]){
	count++;
	break;
      }
      else if (T[i] < S[mid])
	right = mid;
      else
	left = mid + 1;
    }
  }
  printf("%d\n",count);
    
  return 0;
}

