#include<stdio.h>

int main(){
  int n,q,S[100000],T[50000],i,left,right,mid,count=0;

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

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

  return 0;
}
      