#include <cstdio>

const int maxn = 1000001;
const int maxp = 570000;

FILE *in = fopen("pairs.in","r"), *out = fopen("pairs.out","w");

int n;

int k;
char x[maxn];
int primes[maxp];

int maxnr = -1;

void ciur()
{
    primes[++k] = 2;

    for ( int i = 4; i <= maxp; i += 2 )
        x[i] = 'x';

    for ( int i = 3; i <= maxp; i += 2 )
        if ( x[i] != 'x' )
        {
            primes[++k] = i;

            for ( int j = i+i; j <= maxp; j += i )
                x[j] = 'x';
        }
}

char e[maxn];
int h[maxn];

void read()
{
    fscanf(in, "%d", &n);

    int x = 0;
    for ( int i = 1; i <= n; ++i )
        fscanf(in, "%d", &x), ++e[ x ], x > maxnr ? maxnr = x : 1;
}

void calch()
{
    for ( int i = 2; i <= maxnr; ++i )
        for ( int j = i; j <= maxnr; j += i )
            if ( e[j] )
                ++h[i];
}

long long count()
{
    long long res = 0;

    int nrp = 0;
    int tmp = 0;
    int ee = 0;
    int ok = 1;


    for ( int i = 2; i <= maxnr; ++i )
    {
        ok = 1;
        tmp = i;

        nrp = 0;

        for ( int j = 1; primes[j]*primes[j] <= i; ++j )
        {
            ee = 0;
            int tt = primes[j];
            if ( tmp % tt == 0 )
            {
                ++nrp;
                while ( tmp % tt == 0 && ee < 2 )
                    tmp /= tt, ++ee;

                if ( ee > 1 )
                {
                    ok = 0;
                    break;
                }
            }
        }

        if ( ok )
        {
            if ( tmp > 1 )
                ++nrp;

            if ( (nrp & 1) == 0 )
                res = res - (long long)((h[i]*(h[i] - 1)) >> 1);
            else
                res = res + (long long)((h[i]*(h[i] - 1)) >> 1);
        }
    }

    return res;
}

int main()
{
    ciur();
    read();
    calch();

    long long cnt = (long long)n*(n-1)/2;

    fprintf(out, "%lld\n", cnt - count());

	return 0;
}