#include<cstdio>
using namespace std;
int ok,maxi,val,n,i,j,nr,pr[1009],s[1000009];
char ap[1000009],smn[1000009],nu[1000009],cr[1000009];
long long cat,rez;
int main()
{
    freopen("pairs.in","r",stdin);
    freopen("pairs.out","w",stdout);
    scanf("%d",&n);
    rez=(long long)1LL*n*(n-1)/2;
    while(n)
    {
        n--;
        scanf("%d",&val);
        ap[val]=1;
        if(val>maxi) maxi=val;
    }
    for(i=2;i<=maxi;i++)
    {
        ok=cr[i];
        if(ok==0&&i<=maxi/i)
        {
            val=i*i;
            for(j=val;j<=maxi;j+=val)
                nu[j]=1;
            for(j=i*i;j<=maxi;j+=i)
                cr[j]=1;
        }
        if(ok==0)
        {
            for(j=i;j<=maxi;j+=i)
                smn[j]^=1;
        }
        for(j=i;j<=maxi;j+=i)
            s[i]+=ap[j];
    }
    for(i=2;i<=maxi;i++)
        if(!nu[i])
        {
            cat=(long long)s[i]*(s[i]-1)/2;
            if(smn[i]==1) rez-=cat;
            else rez+=cat;
        }
    printf("%lld\n",rez);
    return 0;
}