#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(void) {
	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;
}
