#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;
}
