#include<stdio.h>

int A[1000000], n;

/*二分探索*/

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;
}

