#include <stdio.h>
int main(){
  int S[100000],T[50000],n,q,i,j,count=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]);
    left=0;
    right=n;  
    while(left < right){
      mid=(left + right)/2;
      if(T[i] == S[mid]){
	count++;
	break;
      }
      else if(T[i] < S[mid]) right = mid;
      else left = mid + 1;
    }
  }
  printf("%d\n",count);
  
  return 0;
}