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