#include <stdio.h>
int p[1000001],b[1000001],d[1000001];
int num[100001],apar[1000001];
int n;
int main()
{
    freopen ("pairs.in","r",stdin);
    freopen ("pairs.out","w",stdout);
    scanf("%d",&n);
    int cap=0;
    for(int i=1;i<=n;i++)
    {
        scanf("%d",&num[i]);
        apar[num[i]]=1;
        if(cap<num[i]) cap=num[i];
    }
    for(int i=2;i<=cap;i++)
    {
        if(p[i]==0)
        {
            d[i]=1;
            for(int j=2;i*j<=cap;j++)
            {
                if(j%i==0) b[i*j]=1;
                p[i*j]=1;
                d[i*j]++;
            }
        }
    }
    //for(int i=1;i<=cap;i++) printf("%d %d\n",i,ap[i]);
    long long sum=0;
    for(int i=2;i<=cap;i++)
    {
        if(b[i]==0)
        {
            int nr=0;
            for(int j=i;j<=cap;j+=i) if(apar[j]==1) nr++;
            if(d[i]%2==1) sum+=(long long)nr*(nr-1)/2;
            else sum-=(long long)nr*(nr-1)/2;
        }
    }
    sum=(long long)n*(n-1)/2-sum;
    printf("%lld\n",sum);
}