#include<stdio.h>
 
int main(){
   
  int i,j,num,num2,count=0,key;
  int NUM[100001];
   
  scanf("%d",&num);
  for(i=0;i<num;i++){
    scanf("%d",&NUM[i]);
     
  }
   
  scanf("%d",&num2);
   
  for(i=0;i<num2;i++){
    scanf("%d",&key);
 
    int left=0,right=num,mid;
    while(left<right){
      mid=(left+right)/2;
      if(NUM[mid]==key){
    count++;
    break;
      }
      else if(key<NUM[mid])
    right=mid;
      
    }
  }
  printf("%d\n",count);  
  
}