#include<stdio.h>
int main()
{
  int left,right,mid,i,count=0;
  int n,s[100000],q,t[50000];
  
  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++) {
    left = 0;
    right = n;
    while(left < right) {
      mid = (left+right)/2;
      if(s[mid] == t[i]) count++;
      if(s[mid]< t[i]) left = mid+1;
      else right = mid;
    }
  }

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

  return 0;
}