#include<stdio.h>
#include<algorithm>
#define maxn 100005
#define maxval 1000005
#define inf 0x3f3f3f3f
using namespace std;

int n,m;
int used[maxval],nr[maxval],sieve[maxval];
long long sol;

void read()
{
    int x;
    scanf("%d",&n);
    for(int i=1;i<=n;i++)
     scanf("%d",&x),m=max(m,x),used[x]=1;
}

void solve()
{
    sol=1LL*n*(n-1)/2;
    for(int i=2;i<=m;i++)
     for(long long j=i;j<=m;j+=i)
      if(used[j]) nr[i]++;

    for(int i=2;i<=m;i++)
     if(!sieve[i])
     {
         sol-=1LL*nr[i]*(nr[i]-1)/2;
         for(long long j=i;j<=m;j+=i) sieve[j]++;
         for(long long j=1LL*i*i;j<=m;j+=1LL*i*i) sieve[j]=-inf;
     }
     else
      if(sieve[i]>1)
      {
         if(sieve[i]%2==0) sol+=1LL*nr[i]*(nr[i]-1)/2;
         else sol-=1LL*nr[i]*(nr[i]-1)/2;
      }
}

int main()
{
    freopen("pairs.in","r",stdin);
    freopen("pairs.out","w",stdout);

    read();
    solve();
    printf("%lld",sol);

    fclose(stdin);
    fclose(stdout);
    return 0;
}