#include <iostream>
#include <fstream>
#define NMAX 1000010
using namespace std;
int vis[NMAX + 1];
long long int n;
int x[NMAX + 1];
int euler[NMAX + 1];
long long int answer;
int vmax;
int nusepoate[NMAX];

void generateEuler() {
    // euler[i] = -1 => are divizori primi cu exponent > 1
    // euler[i] = v > 0 => nr de divizori primi ai lui i este v
    for (int i = 2; i <= vmax; ++i) {
        if (euler[i] == 0) {
            for (int j = i; j <= vmax; j = j + i) {
                euler[j] ++;
                if (j % (i * i) == 0) {
                    nusepoate[j] = 1;
                }
            }
        }
    }
    for (int i = 2; i <= vmax; ++i) {
        if (nusepoate[i] == 0) {
//            long long int currentSum = 0;
//            for (int j = i; j <= vmax; j += i) {
//                currentSum = currentSum + vis[j];
//            }
//            if (euler[i] % 2 == 0) {
//                answer = answer - currentSum;
//            } else {
//                answer = answer + currentSum;
//            }
            if (euler[i] % 2 == 1) {
                answer = answer + (x[i] * (x[i] - 1) / 2);
            } else {
                answer = answer - (x[i] * (x[i] - 1) / 2);
            }
        }
    }

}

int main() {

    ifstream f("pairs.in");
    ofstream g("pairs.out");

    f >> n;
    for (int i = 0; i < n; ++i) {
        int x;
        f >> x;
        vis[x] = 1;
        vmax = max(vmax, x);
    }

    for (int i = 2; i <= vmax; ++i) {
        for (int j = i; j <= vmax; j += i) {
            if (vis[j] != 0) {
                x[i] ++;
            }
        }
    }
    generateEuler();
    g << n * (n - 1) / 2 - answer;


    return 0;
}