#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;
}
