#include<stdio.h>

int A[1000000], n;

int main(){
  int i, q, key, 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",&key);
    if(binarySearch(key)){
      sum++;
    }
  }
  printf("%d\n",sum);

  return 0;
}

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;
}
	
