#include <iostream>
#include <fstream>
#define nmx 1000000
#define ll long long

using namespace std;
ifstream fin("pairs.in");
ofstream fout("pairs.out");

ll rez,n,nr;
int i,j,mx;
int p[nmx+5];
bool f[nmx+5],v[nmx+5];

int cmmdc(int a,int b)
{int r=a%b;while(r){a=b;b=r;r=a%b;}return b;}

int main()
{
	fin>>n;
	for(i=1;i<=n;i++)
		fin>>j, v[j]=1, mx=max(mx,j);
	f[1]=1;
	for(i=2;i<=mx;i++)
		if(f[i]==0)
		{
			p[i]=1;
			for(j=i*2;j<=mx;j+=i)
				f[j]=1;
		}
	rez=0;
	for(i=2;i<=mx;i++)
		if(p[i]>=1)
		{
			nr=0;
			for(j=1;j*i<=mx;j++)
			{
				if(f[j]==0&&i%j!=0) p[i*j]++;
				if(v[i*j]==1)   nr++;
			}
			nr=nr*(nr-1)/2;
			if(p[i]%2==1)   rez+=nr;
			else            rez-=nr;
		}
	fout<<n*(n-1)/2-rez<<"\n";
}