#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, k, q, 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;
}
