#include <bits/stdc++.h>
#define maxN 1000005
using namespace std;
int nrp[maxN];
bool seen[maxN],sqrd[maxN];
int n,i,j,val,maxx;
long long sol;
int main()
{
    freopen("pairs.in","r",stdin);
    freopen("pairs.out","w",stdout);
    scanf("%d",&n);
    for(i=1;i<=n;i++)
        scanf("%d",&j),
        seen[j]=true,
        maxx=max(maxx,j);
    for(i=2;i<=maxx;i++)
        if(!nrp[i])
            for(j=i;j<=maxx;j+=i)
            {
                nrp[j]++;
                if(i*i<=maxx && j%(i*i)==0)
                    sqrd[j]=true;
            }
    for(i=1;i<=maxx;i++)
        if(!sqrd[i])
        {
            val=0;
            for(j=i;j<=maxx;j+=i)
                if(seen[j])
                    val++;
            if(nrp[i]%2)
                sol-=1LL*val*(val-1);
            else sol+=1LL*val*(val-1);
        }
    printf("%lld",sol/2);
    return 0;
}