#include<stdio.h>

int a[1000000],n;
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;
		if( key > a[mid] )left = mid+1;
		else if( key < a[mid] )right = mid;
	}
	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;
	}