#include<fstream>
using namespace std;
ifstream fin("pairs.in");
ofstream fout("pairs.out");
const int nmax = 1000001;
long long n, i, j, sol, maxx, x, nr, v[nmax];
bool e[nmax];

int main()
{
    fin >> n;
    sol=n*(n-1)/2;
    for(i=1; i<=n; ++i)
    {
        fin >> x;
        maxx=max(x, maxx);
        e[x]=1;
    }
    for(i=2; i<=maxx; ++i)
        if(!v[i])
            for(j=i; j<=maxx; j+=i)
                v[j]++;

    for(i=2; i*i<=maxx; ++i)
        for(j=i*i; j<=maxx; j+=i*i)
            v[j]=-1;

    for(i=2; i<=maxx; ++i)
        if(v[i]!=-1)
        {
            nr=0;
            for(j=i; j<=maxx; j+=i)
                if(e[j]) ++nr;
            if(v[i]%2==0) sol+=nr*(nr-1)/2;
            else sol-=nr*(nr-1)/2;
        }
    fout << sol << '\n';
    return 0;
}