#include <stdio.h>
#define N 1<<17
#define P 1<<20
int n,maxim,nr[P],fact[P];
char v[N];
long long rez;
char cbin(int x)
{
	int i,step;
	for (step=1; step<=n; step<<=1);
	for (i=0; step; step>>=1)
		if (i+step<=n && v[i+step]<=x)
			i+=step;
	if (v[i]==x)
		return 1;
	return 0;
}
void precalcul()
{
	int i,j;
	nr[1]=n;
	for (i=2; i<=maxim; i++)
		for (j=i; j<=maxim; j+=i)
			nr[i]+=v[j];
}
void solve()
{
	int i,j;
	for (i=2; i<=maxim; i++)
		if (!fact[i])
			for (j=i; j<=maxim; j+=i)
				fact[j]++;
	for (i=1; i<=maxim; i++)
		if (fact[i]&1)
			rez+=(long long)nr[i]*(nr[i]-1)/2;
		else
			rez-=(long long)nr[i]*(nr[i]-1)/2;
}
int main()
{
	freopen("pairs.in","r",stdin);
	freopen("pairs.out","w",stdout);
	scanf("%d",&n);
	int i,x;
	for (i=1; i<=n; i++)
	{
		scanf("%d",&x);
		v[x]=1;
		maxim=x>maxim ? x : maxim;
	}
	rez=(long long)n*(n-1)/2;
	precalcul();
	solve();
	printf("%lld\n",rez);
	return 0;
}