#include <stdio.h>
#define ll long long
  
bool v[1000001];
  
ll ciur[1000001];
  
int main()
{
  
    ll m=0,n=0,i,j,x,t,sol=0;
  
    freopen("pairs.in","r",stdin);
    freopen("pairs.out","w",stdout);
  
    scanf("%lld\n",&n);
  
    sol=n*(n-1)/2;
  
    for (i=1;i<=n;++i)
    {
  
        scanf("%lld",&x);
  
        v[x]=1;
  
        if (x>m)
  
            m=x;
  
    }
  
    for (i=2;i<=m;++i)
        if (!ciur[i])
            for (j=i;j<=m;j+=i)
                ++ciur[j];
  
    for (i=2;i*i<=m;++i)
        for (j=i*i;j<=m;j+=i*i)
            ciur[j]=-1;
  
    for (i=2;i<=m;++i)
        if (ciur[i]!=-1)
        {
  
            t=0;
  
            for (j=i,t=0;j<=m;j+=i)
                if (v[j])
                    ++t;
  
            sol-=((ciur[i]%2)*2-1)*t*(t-1)/2;//formula
  
        }
  
    printf("%lld\n",sol);
  
    return 0;
  
}