#include<iostream>
#include<fstream>

using namespace std;

int v[100000];
int main()
{

    int n,i,x,j,y,nr=0;
    ifstream in("pairs.in");
    ofstream out("pairs.out");
    in>>n;
    for (i=1;i<=n;++i)
      in>>v[i];

      for (i=1;i<=n;++i)

            for (j=1;j<=n;++j)
if (v[i]!=v[j])
        {
           x=v[i];
           y=v[j];
            while (x!=y) {if (x>y) x=x-y; else y=y-x;}
            if (x==1) nr++;



        }
 out<<nr/2;

    return 0;
}