#include<stdio.h>

#define N 100000
#define Q 50000

int main(){
  int i,n,q,count=0;
  int left,right,mid;
  int S[N],T[Q];
  scanf("%d",&n);
  for(i=0;i<n;i++){
    scanf("%d",&S[i]);
  }
  scanf("%d",&q);
  for(i=0;i<q;i++){
    scanf("%d",&T[i]);
  }

  for(i=0;i<q;i++){
    left=0;
    right=n;
    while(left<right){
      mid=(left+right)/2;
      if(T[i]==S[mid]){
	  count++;
	  break;
	}
	if(T[i]>S[mid]){
	  left=mid+1;
	}else if(T[i]<S[mid]){
	  right=mid;
	}
    }
  }
  printf("%d\n",count);
  return 0;
}