#include <stdio.h>
 
int isIncludedInS(int x);
 
int n,q;
int S[100000];
int count = 0;
 
main(){
 
  int i;
  int tmp;
 
  scanf("%d",&n);
  for(i=0; i<n; i++){
    scanf("%d",&S[i]);
  }
 
  scanf("%d",&q);
  for(i=0; i<q; i++){
    scanf("%d",&tmp);
    count += isIncludedInS(tmp);
  }
 
  printf("%d\n",count);
 
  return 0;
 
}
 
int isIncludedInS(int x){
 
  int i,j;
  int min,max;
  int middle;
 
  min = 0;
  max = n-1;
  while(min <= max){
    middle = (max+min)/2;
    if(x > S[middle]){
      min = middle + 1;
    }else if(x < S[middle]){
      max = middle - 1;
    }else if(x == S[middle]){
      return 1;
    }
  }
  return 0;
 
}