#include<stdio.h>
int n, S[100000];

int binarySearch(int key){
  int left = 0, middle,  right = n;
  while(left < right){
    middle = (left + right) / 2;
    if(S[middle] == key)  return 1;
    if(key < S[middle])   right = middle;
    else                           left = middle+1;
  }

  return 0;
}

int main(){
  int q, T[100000], i, cnt = 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++){
    if(binarySearch(T[i])){
      cnt++;
    }
  }

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

  return 0;
}