#include<stdio.h>
#define DIM 1000023
#define LL long long int
FILE *fin, *fout;
bool check[DIM];
LL v[DIM];
LL n,max=0,i,j,sol,x;
 
int main()
{
    fin = freopen("pairs.in","r",stdin);
    fout = freopen("pairs.out","w",stdout);
    scanf("%lld",&n);
    sol=n*(n-1)/2;
    for(i=1;i<=n;i++)
    {
        scanf("%lld",&x);
        check[x]=1;
        if(x>max)
            max=x;
    }
    for(i=2;i<=max;i++)
        if(v[i]==0)
            for(j=i;j<=max;j+=i)
                ++v[j];
    for(i=2;i*i<=max;i++)
        for(j=i*i;j<=max;j+=i*i)
            v[j]=-1;
    for(i=2;i<=max;i++)
    {
        if(v[i]!=-1)
        {
            x=0;
            for(j=i;j<=max;j=j+i)
                if(check[j])
                    ++x;
            if(v[i]%2) sol -= x*(x-1)/2;
            else sol += x*(x-1)/2;
        }
    }
    printf("%lld\n",sol);
    fclose(fin);
    fclose(fout);
    return 0;
}