#include <iostream>
#include <cstdio>
#define MAXVAL 1000050

using namespace std;

int n, a[MAXVAL];
int viz[MAXVAL], nq, out[MAXVAL];

void ciur()
{
    for (int i = 2; i < MAXVAL; i++)
    {
        if (!viz[i]) {
            for (int j = i; j < MAXVAL; j += i)
                viz[j]++;
            if (1LL*i*i >= MAXVAL) continue;
            for (int j = i*i; j < MAXVAL; j += i*i)
                out[j]++;
        }
    }
}

void solve()
{
    int rez = 0;
    for (int i = 1; i < MAXVAL; i++)
    {
        if (out[i]) continue;
        int cate = 0;
        for (int j = i; j < MAXVAL; j += i)
            cate += a[j];
        /// PINEX
        if (viz[i] & 1)
            rez -= cate*(cate-1);
        else
            rez += cate*(cate-1);
    }
    printf("%d", rez/2);
}

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

    scanf("%d", &n);
    for (int i = 1; i <= n; i++) {
        int x;
        scanf("%d", &x);
        a[x] = 1;
    }
    ciur();
    solve();

    return 0;
}