#include<fstream>
using namespace std;
long res[1000001],n,s,t,x,ma,j;
long prim[]={0,2,3,5,7,11,13,17,19,23,29,31,37,41,43,47,53,59,61,67,71,73,79,83,89,97,101,103,107,109,113,127,131,137,139,149,151,157,163,167,173,179,181,191,193,197,199,211,223,227,229,233,239,241,251,257,263,269,271,277,281,283,293,307,311,313,317,331,337,347,349,353,359,367,373,379,383,389,397,401,409,419,421,431,433,439,443,449,457,461,463,467,479,487,491,499,503,509,521,523,541,547,557,563,569,571,577,587,593,599,601,607,613,617,619,631,641,643,647,653,659,661,673,677,683,691,701,709,719,727,733,739,743,751,757,761,769,773,787,797,809,811,821,823,827,829,839,853,857,859,863,877,881,883,887,907,911,919,929,937,941,947,953,967,971,977,983,991,997};
long verif(long x)
{
    long i,nr=0;
    for(i=1;prim[i]<=x;i++)
    {
        if(x%(prim[i]*prim[i])==0)
            return 0;
        if(x%prim[i]==0)
        {
            nr++;
        }
    }
    return nr;
}
int main()
{
    ifstream f("pairs.in");
    ofstream g("pairs.out");
f>>n;
long i;
for(i=1;i<=n;i++)
    {
        f>>x;
        ma=max(ma,x);
        for(j=2;j<=x/2;j++)
            if(x%j==0)
            {
                res[j]++;
            }
        res[x]++;
    }
s=((n-1)*n)/2;
for(i=2;i<=ma;i++)
{
    if(res[i]>1)
    {
        t=verif(i);
        if(t>0)
            {
                if(t%2==0)
                    s+=(res[i]*(res[i]-1))/2;
                else
                    s-=(res[i]*(res[i]-1))/2;
            }
    }
}
g<<s;
return 0;
}