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

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

  scanf("%d", &n);
  for( i = 0 ; i < n ; i++){
    scanf("%d", &S[i]);
  }
  scanf("%d", &q);
  for( j = 0 ; j < q ; j++){
    scanf("%d", &T[j]);
  }
  
  for( i = 0 ; i < q ; i++){
    left = 0;
    right = n;
    while(left < right){
      mid = (left + right)/2;
      if(T[i] == S[mid]){
	count++;
	break;
      }
      if(T[i] > S[mid]){
	left = mid + 1;
      }
      else if(T[i] < S[mid]){
	right = mid;
      }
    }
  }

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