#include <stdio.h>
 
#define N 100000
#define Q 50000
 
int BinarySearch();
 
int main() {
  
int n,q,S[N],T[Q];
int i,key,num,sum=0;
 
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++){
 
num = BinarySearch(n,S,T[i]);
 if(num != 0)
   sum++;
}
 
printf("%d\n",sum);
 
 
return 0;
}
 
int BinarySearch(int n,int S[],int key){
 
  int left,mid,right;
   
  left = 0;
  right = n;
 
  while (left < right){
     
    mid = (left + right)/2;
     
    if( key == S[mid])
      return 1;
 
    if( key > S[mid] )
      left = mid +1;
     
    else if( key < S[mid] )
      right = mid;
  }
 
  return 0;
 
}