#include<stdio.h>

int A[1000000],n;

//線形探索
int binarySearch(int key){
	int left=0;
	int right=n;
	int mid;
	while(left<right){
		mid=(left+right)/2;
		if(key==A[mid])return 1;	//keyを発見
		if(key>A[mid])left=mid+1;	//後半を探索
		else if(key<A[mid])right=mid;//前半を探索
	}
	return 0;
}

int main(){
	int i,q,k,sum=0;
	
	scanf("%d",&n);
	for(i=0;i<n;i++)scanf("%d",&A[i]);
	
	scanf("%d",&q);
	for(i=0;i<q;i++){
		scanf("%d",&k);
		if(binarySearch(k))sum++;
	}
	printf("%d\n",sum);
	
	return 0;
}