#include<stdio.h>


int main(){
  int n,q,S[10000],T[500];
  int i,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(T[i]==S[mid] ||T[i]==S[left] ||T[i]==S[right] ){
	count++;
	break;
      }
      else if (T[i]>S[mid])
	left=mid+1;
      else if (T[i]<S[mid])
	right = mid;
    }
    
  }
  
  printf("%d\n",count);
  
  return 0;
}

