#include <stdio.h>

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

int main(void)
{
  int i,n,a[1000000],q,key,ans;
  ans=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(a,n,key)){
      ans++;
    }
  }
  printf("%d\n",ans);
  
  return 0;
}