#include<stdio.h>

int main(){
  int n,q,left,right,mid,count=0,i;
  scanf("%d",&n);
  int S[100000];

  for(i=0;i<n;i++){
    scanf("%d",&S[i]);
  }

  scanf("%d",&q);
  int T[50000];

  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(S[mid] == T[i]){
      count++;
      break;
    }else if(T[i] < S[mid]){
      right = mid;
    }else{
      left = mid + 1;
    }
  }
  
  }

  printf("%d\n",count);

  return 0;
}

