#include <stdio.h>

int main()
{
  int s[100000], t[50000], n, q, i, j, count = 0, left, right, mid;
  
  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(t[i] < s[mid])right = mid;
	  else left = mid + 1;
	}
    }

  printf("%d\n",count);
  
  return 0;
}

