#include<stdio.h>

#define N 100000

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

  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++){
    key = T[i];
    left = 0;
    right = n;
    
    while(left < right){
      mid = (left + right) / 2;
      
      if(key == S[mid]){
	count++;
	break;
      }

      if(key > S[mid]) left = mid + 1;
      else if(key < S[mid]) right = mid;
    }
  }

  printf("%d\n", count);
  return 0;
}