#include <fstream>
#include <iostream>
using namespace std;
const int N = 100005;
int a[N], o[N * 10], v[N * 10], n, nr, nr1, MAX;
char p[N * 10];
long long rez = 0;
long long partial = 1;
void back(int k){
	if(k > nr){
//		cout << nr1 << " " << partial << " " << v[partial] << '\n';
		if(nr1 % 2)
			rez -= 1LL * ((v[partial] * (v[partial] - 1)) / 2);
		else
			rez += 1LL * ((v[partial] * (v[partial] - 1)) / 2);
	}
	else
	for(int i = 0; i <= 1; ++i){
		if(i == 1){
			++nr1;
			partial = 1LL * partial * a[k];
		}
		if(partial <= 1LL * MAX)
			back(k + 1);

		if(i == 1){
			--nr1;
			partial = (long long) partial / a[k];
		}
	}
}

int main(){
	ifstream fin("pairs.in");
	ofstream fout("pairs.out");
	int i, j;
	fin >> n;
	for(i = 1; i <= n; ++i)
		fin >> a[i], o[a[i]] = 1;
	for(i = 1; i <= n; ++i)
		if(a[i] > MAX)
			MAX = a[i];

	for(i = 2; i <= MAX; ++i){
		for(j = i; j <= MAX; j += i)
			if(o[j])
				++v[i];
	}
	
	for(i = 2; i <= MAX; ++i)
		if(p[i] == 0)
			for(j = i + i; j <= MAX; j += i)
				p[j] = 1;
			
	rez = n * (n - 1);	rez /= 2;
	nr = 0;
	for(i = 2; i <= MAX; ++i)
		if(p[i] == 0)
			a[++nr] = i;

	back(1);
//	for(i = 1; i <= nr; ++i)
//		fout << a[i] << '\n';
	fout << rez << '\n';

	return 0;
}