#include <bits/stdc++.h>
using namespace std;
ifstream f("pairs.in");
ofstream g("pairs.out");
#define int long long
const int Max = 1e6 + 1;
void nos()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
}
int n;
vector < int > multime;
int maxx;
void read()
{
    f>>n;
    int i;
    for(i=1;i<=n;i++)
    {
        int x;
        f>>x;
        maxx = max(maxx,x);
        multime.push_back(x);
    }
}

int divisible[Max];
int dp[Max];
void baga(int n)
{
    int d ;
    if(n%2 == 0 and n!=2)
    {
        divisible[2] ++;
        divisible[n / 2] ++;
    }
    for(d=3;d*d<=n;d+=2)
    {
        if(n%d == 0)
        {
            divisible[d]++;
            int div = n / d;
            if(d!=div)
            divisible[div]++;
        }

    }
    divisible[n] ++;
    divisible[1] ++;

}
void solve()
{
    for(auto it : multime)
        baga(it);
    //dp[i] nr de perechi care au cmmdc i
    //un fel de ciur invers?

    int i,j;
    for(i = maxx; i>= 1;i--)
    {
        int val = divisible[i];
        dp[i] = (val*(val-1)) / 2;
        for(j=2;j<=maxx / i; j++)
            dp[i] -= dp[i*j];
        //scadem multipli, principiul includerii excluderii
    }
    g<<dp[1];
}
void restart()
{

}

int32_t main()
{

        read();
        solve();
        restart();
    return 0;
}