#include <cstdio>

using namespace std;

const int mil = 1000000;

int n,c[mil+2];
long long r;
bool a[mil+2];

int main() {
    freopen("pairs.in", "r", stdin);
    freopen("pairs.out", "w", stdout);

    scanf("%d", &n);
    for(int i = 1; i <= n; ++i) {
        int aux;
        scanf("%d", &aux);
        a[aux] = true;
    }

    for(int i = 2; i <= mil; ++i)
        if(not c[i])
            for(int j = i; j <= mil; j += i)
                ++ c[j];

    for(int i = 2; i * i <= mil; ++i)
        for(int j = i * i; j <= mil; j += i * i)
            c[j] = 0;

    r = (1LL*n*n-n)/2;

    for(int i = 2; i <= mil; ++i)
        if(c[i]) {
            int aux = 0;
            for(int j = i; j <= mil; j += i)
                if(a[j])
                    ++ aux;

            if(c[i] & 1)
                r -= (1LL*aux*aux-aux)/2;
            else
                r += (1LL*aux*aux-aux)/2;
        }

    printf("%lld\n", r);

    return 0;
}