#include<stdio.h>

int main(){
  int i,j;
  int n,q;
  int left,right;
  int count=0;
  int mid;

  scanf("%d",&n);
  int S[n];
  for(i=0;i<n;i++){
    scanf("%d",&S[i]);
  }
  scanf("%d",&q);
  int T[q];
  for(i=0;i<q;i++){
    scanf("%d",&T[i]);
  }
  
  for(i=0;i<q;i++){
    left=0;
    right=n;
    while(left < right){
      if(T[i]>right)break;
      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;
}


