#include<stdio.h>
#define N 1000000
#define Q 50000

int main()
{

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