#include <bits/stdc++.h>
using namespace std;
const int VMAX = 1e6+2;
int n,ap[VMAX],cnt[VMAX],mobius[VMAX];

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

signed main()
{
    fin >> n;
    for(int i = 1; i <= n; i++){
        int x;
        fin >> x;
        ap[x] = 1;
    }
    mobius[1] = 1;
    for(int i = 1; i < VMAX; i++){
        cnt[i] = ap[i];
        for(int j = 2*i; j < VMAX; j += i){
            mobius[j] -= mobius[i];
            cnt[i] += ap[j];
        }
    }
    auto sgauss = [&](int n) -> long long {
        return (1ll*n*(n-1)/2);
    };
    long long ans = sgauss(n);
    for(int i = 2; i < VMAX; i++){
        ans += mobius[i] * sgauss(cnt[i]);
    }
    fout << ans;
    return 0;
}