#include <bits/stdc++.h>

using namespace std;

ifstream fin("pairs.in");
ofstream fout("pairs.out");
const int Max = 1000000;
int n, i, j, a, fr[Max + 2];
int cmmdc[Max + 2];

int main() {
    fin >> n;
    for(i = 1; i <= n; i++) {
        fin >> a;
        fr[a]++;
    }

    for(i = Max; i >= 1; i--) {
        //cmmdc[i] = fr[i];
        for(j = i; j <= Max; j += i) cmmdc[i] += fr[j];

        cmmdc[i] = cmmdc[i] * (cmmdc[i] - 1) / 2;

        for(j = 2 * i; j <= Max; j += i) cmmdc[i] -= cmmdc[j];
    }

    fout << cmmdc[1];

    return 0;
}