#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;
}
