# include <fstream>
# include <bitset>
# define DIM 1000010
using namespace std;
ifstream fin("pairs.in");
ofstream fout("pairs.out");
bitset<DIM> b;
int d[DIM],f[DIM],nr[DIM],p[DIM],v[DIM/10],e[DIM/10],n,k,x,i,j,val,maxim;
long long sol;
int main () {
    fin>>n;
    for(i=1;i<=n;i++){
        fin>>x;
        f[x]=1;
        v[i]=x;
        maxim=max(maxim,x);
    }
    for(i=2;i*i<=maxim;i++)
        if(p[i]==0)
            for(j=2*i;j<=maxim;j+=i)
                p[j]=1;
    for(i=2;i<=maxim;i++)
        if(p[i]==0)
            e[++k]=i;
    for(i=1;i<=n;i++){
        x=v[i];
        for(j=1;j<=k&&e[j]*e[j]<=v[i]&&x!=1;j++)
            if(x%e[j]==0){
                b[e[j]]=1;
                while(x%e[j]==0)
                    x/=e[j];
            }
        if(x!=1)
            b[x]=1;
    }
    for(i=1;i<=maxim;i++)
            d[i]=1;
    for(i=2;i<=maxim;i++)
        if(d[i]==1&&b[i]==1)
            for(j=i;j<=maxim;j+=i){
                d[j]*=i*(1-p[i]);
                nr[j]++;
            }
    for(i=1;i<=maxim;i++){
        if(d[i]==i){
            val=0;
            for(j=i;j<=maxim;j+=i)
                if(f[j])
                    val++;
            if(nr[i]%2==0)
                sol+=(1LL*val*(val-1))/2;
            else
                sol-=(1LL*val*(val-1))/2;
        }
    }
    fout<<sol<<"\n";
    return 0;
}