#include <cstdio>
#include <bitset>
#define filein "pairs.in"
#define fileout "pairs.out"
#define MAXN 1000002
using namespace std;

bitset <MAXN> NotPrime;
bitset <MAXN> Used;
bitset <MAXN> BigPow;
int Divisors[MAXN];

int N;
int maxx;
long long Answer;

void ReadData();
void PrintData();

void Erathostenes();

int main()
{
    ReadData();
    Erathostenes();
    register int i,j;
    int x;
    for (i=2; i<=maxx; i++)
    {
        if (!BigPow[i])
        {
            x=0;
            for (j=i; j<=maxx; j+=i)
                x+=Used[j];
            if (Divisors[i]%2==0) Answer-=(1LL*x*(x-1)/2);
            else Answer+=(1LL*x*(x-1)/2);
        }
    }
    Answer=(1LL*N*(N-1)/2)-Answer;
    PrintData();
    return 0;
}

void ReadData()
{
    FILE *in;
    in=fopen(filein,"r");
    fscanf(in,"%d",&N);
    register int i;
    int x;
    for (i=1; i<=N; i++)
    {
        fscanf(in,"%d",&x);
        Used[x]=1;
        if (maxx<x) maxx=x;
    }
    fclose(in);
}

void PrintData()
{
    FILE *out;
    out=fopen(fileout,"w");
    fprintf(out,"%lld",Answer);
    fclose(out);
}

void Erathostenes()
{
    register int i,j;
    for (i=2; i<=maxx; i++)
    {
        if (!NotPrime[i])
            for (j=i; j<=maxx; j+=i)
            {
                NotPrime[j]=1;
                Divisors[j]++;
                if (j%(i*i)==0) BigPow[j]=1;
            }
    }
}