#include<bits/stdc++.h>
using namespace std;

int i,n,aux,a[1000005];
long long rs;

int main()
{
  ifstream cin("pairs.in");
  ofstream cout("pairs.out");

  ios_base::sync_with_stdio(0); cin.tie(0);

  cin>>n; rs=(1LL*n*n-n)/2;

  while(n--)
  {
    cin>>aux;
    for(i=2;i*i<=aux;++i)
    if(aux%i==0)
    {
      ++a[i];
      while(aux%i==0) aux/=i;
    }

    if(aux>1) ++a[aux];
  }

  for(i=2;i<=1e6;++i) rs-=(1LL*a[i]*a[i]-a[i])/2;

  cout<<rs<<'\n';

 return 0;
}