#include <iostream>
#include <fstream>
#define nmx 1000000

using namespace std;
ifstream fin("pairs.in");
ofstream fout("pairs.out");

int n,i,j,nr,mx;
int p[nmx+5];
bool f[nmx+5],v[nmx+5];

int main()
{
    fin>>n;
    for(i=1;i<=n;i++)
        fin>>j, v[j]=1, mx=max(mx,j);
    f[1]=1;
    for(i=2;i<=mx;i++)
        if(f[i]==0)
        {
            p[i]=1;
            for(j=i*2;j<=mx;j+=i)
                f[j]=1;
        }
    long long rez=0;
    for(i=2;i<=mx;i++)
        if(p[i]>=1)
        {
            nr=0;
            for(j=1;j*i<=mx;j++)
            {
                if(f[j]==0) p[i*j]++;
                if(v[i*j]==1)   nr++;
            }
            nr=nr*(nr-1)/2;
            if(p[i]%2==1)   rez+=nr;
            else            rez-=nr;
        }
    fout<<n*(n-1)/2-rez<<"\n";
}