#include<stdio.h>

int main()
{
  int n, q, i, cnt=0;
  int mid, left, right;
  int s[10000], t[500];

  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(t[i] == s[mid])
	    {
	      cnt++;
	      break;
	    }
	  if(t[i] > s[mid])
	    {
	      left = mid+1;
	    }
	  else if(t[i] < s[mid])
	    {
	      right = mid;
	    }
	}
    }

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