#include<stdio.h>

int n, A[100000];                  /*??°??????????´??????????*/

int binarySearch(int k)            /*?????°??? k ??¨??????????????????*/
{
   int left = 0;
   int right = n;
   int mid;

   while (left<right){
      mid = (left+right)/2;
      if (A[mid]==k)               /*key ?????????*/
         return mid;                  /*??????(key)???????????????*/
      else if (key<A[mid])         /*?????????????´¢*/
         right = mid-1;               /*left mid mid ??¨????????????????¶???±*/
      else                         /*?????????????´¢*/
         left = mid+1;                /*else if ((key)>A[mid]) ?????¨??????????????¢?´¢??¨????§?*/
   }
   return 0;
}

int main()
{
   int i, q, key, sum=0;

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

   scanf("%d", &q);
   for (i=0; i<q; i++){
      scanf("%d", &key);
      if (binarySearch(key))        /*????????¢?´¢??¢??°??? key ????????¨?????????*/
         sum++;
   }

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

   return 0;
}