#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;
bool t[dmax];

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