#include <fstream>

using namespace std;
long long n,i,j,ap,nr,sol,d,p,e,maxim,x[1000001],a;
int f[1000001];
ifstream fin ("pairs.in");
ofstream fout ("pairs.out");

int main (){

    fin>>n;
    for (i=1;i<=n;i++){
        fin>>a;
        f[a] = 1;
        maxim = max (maxim,a);
    }
    for (i=2;i<maxim;i++)
        if (x[i] == 0)
            for (j=i;j<=maxim;j+=i) // aici vedem cati factori primi sunt in descompunerea unui nr
                x[j]++;
    for (i=2;i*i<=maxim;i++)
        for (j=i*i;j<=maxim;j+=i*i)
            x[j] = -1;
    for (i=2;i<=maxim;i++){
        if (x[i] == -1) continue;
        nr = 0;
        for (j=i;j<=maxim;j+=i)
            if (f[j] == 1)
                nr++;
        if (x[i]%2 == 0)
            sol -= 1LL*nr*(nr-1)/2;
        else
            sol += 1LL*nr*(nr-1)/2;

    }
    fout<<1LL*n*(n-1)/2 - sol;


    return 0;
}