#include<stdio.h>

int main(){

  int n,q,i,j,k,C=0,m,r,l;
  int S[100000];
  int T[50000];

  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++){
      r=n-1;
      l=0;
      while(1){
	m=(r-l)/2;
	if(S[m]>T[i]){
	  if((r-l)%2!=0)r=m-1; 
	  else r=m;
	}
	  else if(S[m]<T[i]){
	    if((r-l)%2!=0)l=m+1;
	    else l=m;
	  }
	  else{
	  C++;
	  break;
	}
      }
      if((r-l)==2) break;
    }	
  printf("%d\n",C);
  return 0;
}

