#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;
    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;
}
