#include<bits/stdc++.h>
using namespace std;
int n,x,mv,nr[1000005],sqrd[1000005];
bool seen[1000005];
long long sol,perechi;
inline int max(int a,int b)
{
    return a>b?a:b;
}
int main()
{
    freopen("pairs.in","r",stdin);
    freopen("pairs.out","w",stdout);
    scanf("%d",&n);
    for(int i=1;i<=n;i++)
    {
        scanf("%d",&x);
        seen[x]=1;
        mv=max(mv,x);
    }
    for(int i=2;i<=mv;i++)
    {
        if(!nr[i])
        {
            for(int j=i;j<=mv;j+=i)
            {
                nr[j]++;
                if((1LL*(i*i))<=(1LL*mv) && !(j%(i*i))) sqrd[j]=1;
            }
        }
    }
    for(int i=2;i<=mv;i++)
    {
        if(!sqrd[i])
        {
            int val=0;
            for(int j=i;j<=mv;j+=i)
            {
                if(seen[j]) val++;
            }
            long long perechi=((1LL*val*(val-1))>>1LL);
            if(nr[i]%2)
            {
                sol=sol+perechi;
            }
                else
                sol=sol-perechi;
        }
    }
    printf("%lld\n",sol);
    return 0;
}