#include <stdio.h>
#define P 1<<25
int n,maxim,nr[P],fact[P];
char v[P];
long long rez;
void precalcul()
{
	int i,j;
	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]==0)
		{
			for (j=i*i; j<=maxim; j+=i*i)
				fact[j]=-1;
			for (j=i; j<=maxim; j+=i)
				if (fact[j]>=0)
					fact[j]++;
		}
	for (i=2; i<=maxim; i++)
		if (fact[i]>0)
			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;
	}
	precalcul();
	solve();
	rez=(long long)n*(n-1)/2-rez;
	printf("%lld\n",rez);
	return 0;
}