#include <fstream>
#include <cstring>
#include <cmath>
#define maxn 1000000
#define MAX 1000100
using namespace std;
long long x[MAX];
int m,divizori[MAX],a,n,rad;
long long prod,sol;
bool in[MAX],no[MAX];

void ciur()
{
	for(int i=2;i<=1000000;i++)
	if(!divizori[i])
	{
		divizori[i]=1;
		for(int j=i+i;j<=1000000;j+=i) divizori[j]++;
	}
}
int main()
{
	int i,j;
	ifstream fi("pairs.in");
	ofstream fo("pairs.out");
	fi>>n;
	rad=(int)sqrt((double)n);
	sol=n*(n-1)/2;
	ciur();
	for(i=1;i<=n;i++) 
	{
		fi>>a;
		in[a]=1;
	}
	for(i=2;i<=maxn;i++)
	for(j=i;j<=maxn;j+=i) 
		if(in[j]) x[i]++;
	for(i=2;i<=rad;i++)
	for(j=1;i*i*j<=maxn;j++) 
	no[i*i*j]=1;
	for(i=2;i<=maxn;i++)
	if(x[i]>1 and !no[i])
	{
		if(divizori[i]%2) sol-=(long long)x[i]*(x[i]-1)/2; else sol+=(long long)x[i]*(x[i]-1)/2;
	}
	fo<<sol<<"\n";
	return 0;
}