#include<stdio.h>
#include<math.h>
bool b[1000002];
unsigned v[1000002];
int main()
{
    freopen("pairs.in","r",stdin);
    freopen("pairs.out","w",stdout);
    long long unsigned s,x,n;
    unsigned ma,l,j,i;
    ma=1000000;
    scanf("%llu",&n);
    for(i=1;i<=n;++i)
    {
        scanf("%llu",&x);
        b[x]=1;
    }
    s=n*(n-1)/2;
    for(i=2;i<=ma;i++)
    if(v[i]==0)
        for(j=i;j<=ma;j=j+i)
            v[j]++;
    l=1000;
    for(i=2;i<=l;i++)
    if(v[i])
    {
        n=i*i;
        for(j=n;j<=ma;j=j+n)
        v[j]=0;
    }
    for(i=2;i<=ma;i++)
    if(v[i])
        {
        x=0;
        for(j=i;j<=ma;j=j+i)
        if(b[j])
        x++;
        if(v[i]%2==1)
        s=s-x*(x-1)/2;
        else
        s=s+x*(x-1)/2;
        }
    printf("%llu\n",s);
    return 0;
}