#include <cstdio>
#include <algorithm>

using namespace std;

int n, v[32768];

int prime(int a,int b)
{
    int k=0;    
    while ((a&1)==0 && (b&1)==0) a>>=1, b>>=1, ++k;
    while (a!=b)
    {
               if ((a&1)==0) a>>=1; else
               if ((b&1)==0) b>>=1; else
               if (a>b) a=(a-b)>>1; else b=(b-a)>>1;          
    }
    return (a<<k)==1;
}

int main()
{
	freopen("pairs.in","r",stdin);
	freopen("pairs.out","w",stdout); 

	unsigned cnt=0;
	
	scanf("%d", &n);
		
	for (int i=1;i<=n;++i)
	   scanf("%d", v+i);
		    
	sort(v+1,v+n+1);
    
	for (int i=1;i<n;++i)    
	 for (int j=i+1;j<=n;++j)
	  if (prime(v[i],v[j])) ++cnt;
      
	printf("%u\n", cnt);  

	return 0;
}


 //by Crawler