#include<stdio.h>
int a[100001],n,i,j,nr;
int euclid(int a, int b)
{int c;
 while (b) {
  c = a % b;
  a = b;
  b = c;
 }
 return a;}
int main()
{freopen("pairs.in","r",stdin);
 freopen("pairs.out","w",stdout);
 scanf("%d",&n);
 for(i=1;i<=n;i++)
 {scanf("%d",&a[i]);
  for(j=1;j<i;j++)
   if(euclid(a[i],a[j])<2) nr++; }
 printf("%d",nr);
 return 0;}