#include<fstream>
#define dmax 1000003
using namespace std;

ifstream in("pairs.in");
ofstream out("pairs.out");
int n, divp[dmax] , nr[dmax];
long long mx , bune , tot ,sol;
bool t[dmax];

int main()
{	long long i,j,k,q;
	in>>n;
	for(i=1;i<=n;i++)
	{	in>>k;
		t[k]=1;
		if(k>mx)
			mx=k;
	}
	in.close();
	for(i=2;i<=mx;i++)
		for(j=i;j<=mx;j+=i)
			if(t[j])
				nr[i]++;
			
	for(i=2;i<=mx;i++)
		if(divp[i]==0)
		{	for(j=i*i;j<=mx;j+=(i*i))
				divp[j]=-1;
			for(j=i;j<=mx;j+=i)
				if(divp[j]>=0)
					divp[j]++;
		}		
		
	for(i=2;i<=mx;i++)
		if(divp[i]>0)
		{	q=nr[i]* (nr[i]-1) /2;
			if(divp[i]&1 )bune+=q;
			else bune-=q;
		}	
	tot=n*(n-1)/2;	
	sol=tot-bune;
	out<<sol;
	out.close();
	return 0;
}