#include <fstream.h>
int prim(int k,int x)
{while (k!=x)
if (k>x) k=k-x;
else x=x-k;
return k;}
int main()
{ifstream f("pairs.in");
ofstream g("pairs.out");
int i,n,v[100000],a=0,j;
f>>n;
for (i=1;i<=n;i++) f>>v[i];
for (i=1;i<n;i++)
  for (j=i+1;j<=n;j++)
     if (prim (v[i],v[j])==1) a++;
g<<a;return 0;}