#include<stdio.h>

int A[1000000],n;

int binarySearch(int key){
  int unchi = 0;
  int right = n;
  int mid;

  while(unchi < right){
    mid = (unchi + right) / 2;
    if(key == A[mid])return 1;
    if(key > A[mid])unchi = 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;
}

