#include <fstream>

#define maxn 100001
#define maxv 1000001

using namespace std;

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

bool sieve[maxv],v[maxv],skip[maxv];
int p[maxn],fac[maxv],nr[maxv],mark[maxv];
int t,tt,n,x,maxval;
long long s,prod;

void erathostenes (int n)
{
    t=1;
    p[1] = 2;

    for (int i=3; i<=n; i+=2)
    {
        int ok=0;
        if (!sieve[i])
        {
            nr[i]++;
            for (int j=i; j<=n; j+=i)
            {
                sieve[j] = 1;
                nr[j]++;
                ok |= v[j];
            }

            if (ok)
            {
                p[++t] = i;
            }
        }
    }
}

int main()
{
    fin>>n;

    for (int i=1; i<=n; ++i)
    {
        fin>>x;
        v[x]=1;

        maxval = max (x,maxval);
    }

    erathostenes (maxval);


    for (int i=1; i<=t; ++i)
    {
        for (long long j=1LL*p[i]*p[i]; j<=maxval; j+= 1LL*p[i]*p[i])
        {
            skip[j]=1;
        }
    }

    for (int i=2; i<=maxval; ++i)
    {
        if (!skip[i])
        {
            for (int j=i; j<=maxval; j+=i)
            {
                if (v[i]) mark[i]++;
            }
        }
    }

    s=0;

    for (int i=1; i<=maxval; ++i)
    {
        if (nr[i]%2)
        {
            s += (1LL*mark[i]*(mark[i]-1)/2);
        }
        else
        {
            s -= (1LL*mark[i]*(mark[i]-1)/2);
        }
    }


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