#include <bits/stdc++.h>
#define NUMMAX 1000005

using namespace std;

/*******************************/
// INPUT / OUTPUT

ifstream f("pairs.in");
ofstream g("pairs.out");
/*******************************/
/// GLOBAL DECLARATIONS

int N;
long long ans;
int x, maxNum;
bool ciur[NUMMAX], sqrd[NUMMAX], freq[NUMMAX];
int nr[NUMMAX];
/*******************************/
/// FUNCTIONS

void ReadInput();
void Solution();
void Output();
/*******************************/
///-------------------------------------
inline void ReadInput()
{
    f >> N;

    for (int i = 1 ; i <= N ; ++ i)
    {
        f >> x;
        freq[x] = true;
        maxNum = max(maxNum, x);
    }
}
///-------------------------------------
inline void Ciur()
{
    for (int i = 2 ; 2 * i <= maxNum ; ++ i)
    {
        if (!ciur[i])
        {
            nr[i] = 1;
            for (int j = 2 * i ; j <= maxNum ; j += i)
            {
                nr[j] ++;
                ciur[j] = true;
                if (j % (i * i) == 0) sqrd[j] = true;
            }
        }
    }
}
///-------------------------------------
inline void Solve()
{
    long long numPairs;
    int dv;
    ans = 1LL * N * (N - 1) / 2;
    for (int i = 2 ; i <= maxNum ; ++ i)
    {
        if (sqrd[i]) continue;
        
        dv = 0;
        for (int j = i ; j <= maxNum ; j += i)
        {
            dv += freq[j];
        }
        
        numPairs = 1LL * dv * (dv - 1) / 2;
        if (nr[i] % 2 == 1)
            ans -= numPairs;
        else
            ans += numPairs;
    }
}
///-------------------------------------
inline void Solution()
{
    Ciur();
    Solve();
}
///-------------------------------------
inline void Output()
{
    g << ans;
}
///-------------------------------------
int main()
{
    ReadInput();
    Solution();
    Output();
    return 0;
}