#include <fstream>
#include <vector>

#define NMAX 1000001
#define DIM 100001

using namespace std;

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

int n;

bool vis[NMAX];

int ok[NMAX];

int f[NMAX];

int v[DIM]; 

long long sol;

int main() {

	fin >> n;

	for (int i = 1; i <= n; i++) {

		fin >> v[i];

		vis[v[i]] = 1;

	}

	for (int i = 2; i < NMAX; i++) {

		for (int j = i; j < NMAX; j += i) {

			if (vis[j])
				f[i]++;

		}

	}

	sol = 1LL * n * (n - 1) / 2;

	for (int i = 2; i < NMAX; i++) {

		if (ok[i]) {

			if (ok[i] == -1)
				continue;

			if (ok[i] % 2 == 0)
				sol -= 1LL * (f[i] * (f[i] - 1)) / 2;
			else
				sol += 1LL * (f[i] * (f[i] - 1)) / 2;

			continue;

		}

		for (int j = i + i; j < NMAX; j += i) {

			ok[j]++;

			if (j % (i * i) == 0)
				ok[j] = -1;

		}

		sol -= 1LL * (f[i] * (f[i] - 1)) / 2;
	
	}

	fout << sol << "\n";

	return 0;

}

//Trust me, I'm the Doctor!
//Miriam e tare!