#include <stdio.h>
#include <vector>
#define N 1000100
using namespace std;

vector <bool> m(N);
int n, nr[N],v;
long long sol;

inline long long combinari(long long x) { return x*(x-1)/2; }

void read()
{
	freopen("pairs.in","r",stdin);
	freopen("pairs.out","w",stdout);
	scanf("%d", &n);
	int t;
	for (int i = 1; i <= n; ++ i)
	{
		scanf("%d", &t);
		m[t] =1;
	}
	sol=combinari(n);
}

void solve()
{
	//int j;
	for (int i = 2; i < N; ++i)
	{
		v=0;
		if (nr[i] == -1)
			continue;
		if (nr[i] == 0)
			for (int j = i; j < N; j+=i)
			{
				if(nr[j] != -1)
					++nr[j];
			}
		//int j;
		for (int j = i; j < N; j+=i)
		{
			if(m[j])
				++v;
		}
		if(i>1000)
			continue;
		int k = i*i;
		for (int j = k; j < N; j+=k)
			nr[j] = -1;
		if (nr[i]%2 == 0)
			sol+=combinari(v);
		else
			sol-=combinari(v);
	}
}
void print(){ printf("%lld\n", sol); }
	
int main()
{
	
	read();
	solve();
	print();
	return 0;
}