#include <stdio.h>

int sol,nr,max=0,i,j,n,k,c[1000005],q;
bool a[1000005],b[1000005],ok[1000005];

FILE *f=fopen("pairs.in","r");
FILE *g=fopen("pairs.out","w");

int main()
{
	fscanf(f,"%d",&n);
	for (i=1;i<=n;i++)
	{
		fscanf(f,"%d",&q);
		a[q]=1;
		if(q>max)max=q;
	}
	for (i=2;i<=max;i++)
		if (!(b[i]))
			for (j=1;j<=max/i;j++)
			{
				b[i*j]=1;
				if (!(j%i)) ok[i*j]=1;
				c[i*j]++;
			}
	for (i=2;i<=max;i++)
		if (!ok[i])
		{
			nr=0;
			for (j=1;j<=max/i;j++)
				if (a[i*j]) nr++;
			if (c[i]%2) sol+=(nr*(nr-1)/2);
				else sol-=(nr*(nr-1)/2);
		}
	fprintf(g,"%d",(n*(n-1)/2)-sol);
	return 0;
}