#include<stdio.h>
#include<string.h>
long n,i,a,f[1000050],x[1000050],j,max;
long long s,aa;
int main()
{
 freopen("pairs.in","r",stdin);
 freopen("pairs.out","w",stdout);
 scanf("%ld",&n);
 for(i=1;i<=n;++i)
    {scanf("%ld",&a);
     if(a>max)max=a;
     f[a]=1;}
 for(i=2;i<=max;++i)
    for(j=i;j<=max;j+=i)
       x[i]+=f[j];
 memset(f,0,sizeof(f));
 long long ii,jj;
 for(ii=2;ii<=max;++ii)
    if(f[ii]==0)
      {for(jj=ii;jj<=max;jj+=ii)
          {if(f[jj]>-1)f[jj]++;}
       for(jj=ii*ii;jj<=max;jj+=ii*ii)
          f[jj]=-1;}
 for(i=2;i<=max;++i)
    if(f[i]>0)
      if(f[i]%2)s+=((long long)x[i]*(x[i]-1)/2);
           else s-=((long long)x[i]*(x[i]-1)/2);
 aa=(long long)n*(n-1)/2-s;
 printf("%lld\n",aa);
 return 0;
}