#include <stdio.h>
#include <vector>
using namespace std;
const int n_max = 1000020;
vector <bool> m(n_max,false);
long long nr[n_max], v[n_max];
long long sol, n, maxim;
void read()
{
	freopen("pairs.in","r",stdin);
	freopen("pairs.out","w",stdout);
	scanf(" %lld", &n);
	
	long long t;
	for (int i = 1; i <= n; ++ i)
	{
		scanf("%lld", &t);
		if (maxim < t)
			maxim = t;
		m[t] =1;
	}
}

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

void solve()
{
	int i, j;
	for (i = 2; i <= maxim; ++i)
	{
		if (nr[i] == -1)
			continue;
		if (nr[i] == 0)
			for (j = i; j <= maxim; j+=i)
			{
				if (nr[j] != -1)
					++nr[j];
				
			}
		int k = i*i;
		for (j = i; j <= maxim; j+=i)
		{
			if (m[j]) 
					++v[i];
		}
		for (j = k; j <= maxim; j+=k)
			nr[j] = -1;
		if (nr[i]%2 == 0)
			sol+=combinari(v[i]);
		else
			sol-=combinari(v[i]);
	}
}

void print()
{
	printf("%lld\n", sol);
}
	
int main()
{
	
	read();
	sol=combinari(n);
	solve();
	print();
	return 0;
}