//check check check
#include<iostream>
#include<vector>
#include<algorithm>
#include<fstream>
#include<queue>
#include<cstring>
#include<map>
#include<iomanip>
#include<set>
#include<unordered_map>

#define ll long long
#define pb(x) push_back(x)

using namespace std;

typedef pair<int,int> ii;

const int NMAX = 1e5+5;
const int VALMAX = 1e6+5;

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


unordered_map<int,bool> mp,viz;
unordered_map<int,int> cntdiv;

int main()
{
    ll i,j;
    int maxim = 1;
    ll N;
    fin>>N;
    ll rez = N*(N-1)/2;
    for(i = 1 ; i <= N ; ++i)
    {
        int x;
        fin>>x;
        mp[x] = 1;
        maxim = max(maxim , x);
    }

    //cnt[i] = cate numere din M sunt divizibile cu i
    for(i = 2 ; i <= N ; ++i)
    {
        if(cntdiv[i] == 0)
        {
            for(j = i ; j <= maxim ; j+= i)
                cntdiv[j]++;

            for(j = i*i ; j <= maxim ; j += i*i)
                viz[j] = 1;
        }

        if(viz[i] == 0)
        {
            ll cnt = 0;
            for(j = i ; j <= maxim ; j += i)
            {
                if(mp[j])
                    cnt++;
            }
            if(cntdiv[i]&1)
            {
                rez -= ((cnt*(cnt-1))>>1);
            }
            else
            {
                rez += ((cnt*(cnt-1))>>1);
            }
        }
    }

    fout<<rez;

    return 0;
}