#include <stdio.h>
#define N 100000
#define Q 50000

int T[Q], S[N];
int n, c = 0;
void binarySearch(int);

int main(){

  int i, q;
 
  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++ ){
    binarySearch(T[i]);
  }
  printf("%d\n", c); 
  return 0;
}

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