#include<bits/stdc++.h>
using namespace std;

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

const int NMAX=100005;
const int MMAX=1000005;

int n,cnt[MMAX];
long long sol;
bitset<MMAX>viz;

int main()
{
    int i,j,x,nr,mx=0;
    fin>>n;sol=(1LL*n*(n-1))/2;
    for (i=1;i<=n;i++)
        {
            fin>>x;
            viz[x]=1;
            mx=max(mx,x);
        }
    for (i=2;i<=mx;i++)
        if (!cnt[i])
            for (j=i;j<=mx;j+=i)
                cnt[j]++;
    for (i=2;i*i<=mx;i++)
        for (j=i*i;j<=mx;j+=i*i)
            cnt[j]=0;

    for (i=2;i<=mx;i++)//propagare
        if (cnt[i]>=1)//e bun
            {
                nr=0;
                for (j=i;j<=mx;j+=i)
                    if (viz[j]==1)
                        nr++;
                if (cnt[i]&1) sol-=(1LL*nr*(nr-1))/2;
                else sol+=(1LL*nr*(nr-1))/2;
            }
    fout<<sol<<"\n";
    return 0;
}