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

int main()
{
  int S[N],T[Q],C=0;
  int n,q,i;
  int left,right,mid,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(S[mid] == key){
	C++;
	break;
      }
      else if (key < S[mid])
	right = mid;
      else left = mid +1;
    }

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