/** Binary Search */

#include <stdio.h>

int main(){
  int i,n,q,cnt=0;
  
 /** S[]
   * the number of S[]
   */
  scanf("%d", &n);
  int S[n]; //+1 is for the sentinel.
  //input data
  for(i=0;i<n;i++){
    scanf(" %d", &S[i]);
  }

 /** T[]
   * the number of T[]
   */
  scanf("%d", &q);
  int T[q];
  //input data
  for(i=0;i<q;i++){
    scanf(" %d", &T[i]);
  }

  /* Linear Search
  */
  for(i=0;i<q;i++){
    int key = T[i]; //??????????????¢?´¢
    int mid, left=0, right=n;
    while(left<right){ //right(??????)??????.
      mid = (left + right) / 2; //?¬????mid (int????°???°???????????¨???) 
      if(S[mid]==key){
        cnt++;
      }else if(key<S[mid]){ //??????????????????
        right = mid; //right=m-1??§???????????????????????????????????????
      }else if(S[mid]<key){ //??????????????????
        left = mid + 1;
      }
    }
  }
  
  printf("%d\n",cnt);
  
  return 0;
}