#include<stdio.h>

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

