#include <iostream>
#include <fstream>
using namespace std;
#define MAXNR 1000005
ifstream fin("pairs.in");
ofstream fout("pairs.out");
bool v[MAXNR];
int n;
int maxnr;
int nr[MAXNR];
long long neprime;
void ciur()
{
    int i,j;
    for (i=2;i<=maxnr;i++)
        if (nr[i]==0)
            for (j=i;j<=maxnr;j=j+i)
                nr[j]++;
    for (i=2;i*i<=maxnr;i++)
        for (j=i*i;j<=maxnr;j=j+i*i)
            nr[j]=-1;
}
void sol()
{
    int i,j;
    for (i=2;i<=maxnr;i++)
    {
        if (nr[i]!=-1)
        {
            int nr1=0;
            for (j=i;j<=maxnr;j=j+i)
                if (v[j])
                    nr1++;
                if (nr[i]%2==1)
                    neprime=neprime+(long long)nr1*(nr1-1)/2;
                else neprime=neprime-(long long)nr1*(nr1-1)/2;
        }
    }
}
int main()
{
    int i;
    fin>>n;
    for (i=1;i<=n;i++)
    {
        int x;
        fin>>x;
        v[x]=1;
        if (x>maxnr)
            maxnr=x;
    }
    ciur();
    sol();
    fout<<(long long)n*(n-1)/2-neprime;
    fin.close();
    fout.close();
    return 0;
}