#include<stdio.h>
#include<math.h>
#include<stdlib.h>
#define N 100000
#define Q 50000
int main(){
  int i,n,q,j,S[N],T[Q],AI=0,left,right,mid;
  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]){
    AI++;
    break;
      }
      if(T[i]>S[mid])
    left=mid+1;
      else if(T[i]<S[mid])
    right=mid;
    }
  }
  printf("%d\n",AI);
   
   
  return 0;
}