#include<stdio.h>

int binarySearch(int);
int A[1000000], n;

int main(){
  int i,q,k,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", &k);
    if(binarySearch(k)) sum++;
  }
  printf("%d\n", sum);
  return 0;
}

int binarySearch(int key){
  int left = 0, right = n, mid;

  while(left < right){
    mid = (left + right) / 2;
    if(key == A[mid]) return 1;
    if(key > A[mid]) left = mid + 1;
    else if(key < A[mid]) right = mid;
  }
  return 0;
}

