#include <stdio.h>
#define N 100000
#define Q 50000
 
int search(int[],int[],int,int);
 
int main(void){
  
  int S[N];
  int T[Q];
  int n,q;
  int i;
  int 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]);
  
  count = search(S,T,n,q);
  
  printf("%d\n",count);
  
  return 0;
}

int search(int S[],int T[],int n,int q){
  
  int i;
  int flag;
  int count=0;
  int min=0;
  int max = n-1;
  int mid;
  
  
  for(i=0;i<q;i++){
    flag=0;
    min = 0;
    max = n-1;
    while(min <= max){
      mid = (min+max)/2;
      
      if(S[mid] == T[i]){
	flag = 1;
	break;
      }
      
      else if(S[mid] < T[i])
	min = mid +1;
      
      else if(S[mid] > T[i])
	max = mid -1;
    }
    if(flag ==1)
      count++;

  }
  
  return count;
}