#include <stdio.h>

int binarySearch(int,int,int);

int main()
{
  
  int count, n, q;

  count = 0;
    
  scanf("%d",&n);
  int S[n];
  for(i=0;i<n;i++){
    scanf("%d",&S[i]);
  }

  scanf("%d",&q);
  int T[q];
  for(i=0;i<q;i++){
    scanf("%d",&T[i]);
  }

  for(i=0;i<q;i++){
    if(binarySearch(n,S,T[i]) != -1){
      count++;
    }
  }

  printf("%d\n",count);

  return 0;
    
}

int binarySearch(int n,int A,int key)
{
  
  int left, right, mid;
  
  left = 0;
  right = n;
  while (left < right){
    mid = (left + right)/2;
    if( key == A[mid]){
      return mid;
    }
    if( key > A[mid]){
      left = mid + 1;
    }
    else if( key < A[mid]){
      right = mid;
    }
  }
  return -1;
}

