#include<cstdio>
#include<fstream>
#include<bitset>
#define nmax 1000100
using namespace std;
long long v[nmax],sol,nr,mx,n;
ifstream cin("pairs.in");
ofstream cout("pairs.out");
bitset<nmax> M;
int main()
{
    long long i,j,x;
    //freopen("pairs.in","r",stdin);
    //freopen("pairs.out","w",stdout);
    //scanf("%lld",&n);
    cin>>n;
    sol=n*(n-1)/2;
    for(;n;n--)
    {
        cin>>x;
        M[x]=1;
        if(x>mx)mx=x;
    }
    for(i=2;i<=mx;i++)
        if(!v[i])
            for(j=i;j<=mx;j+=i)
                v[j]++;
    for(i=2;i*i<=mx;i++)
        for(j=i*i;j<=mx;j+=i*i)
            v[j]=-1;
    for(i=2;i<=mx;i++)
        if(v[i]!=-1)
        {
            nr=0;
            for(j=i;j<=mx;j+=i)
                if(M[j])nr++;
            if(v[i]%2)sol-=(nr*(nr-1))/2;
            else sol+=(nr*(nr-1))/2;
        }
    cout<<sol<<"\n";
    return 0;
}