#include <fstream>

using namespace std;
long long v[100000];
int main()
{
    fstream f("pairs.in", ios::in), g("pairs.out", ios::out);
    int i,x,y,r,nr=0,a,b,j;
    long long n;
    f>>n;
    for(i=0;i<n;i++)
        f>>v[i];
    for(i=0;i<n;i++)
        for(j=i+1;j<n;j++)
    {
       x=v[i];
       y=v[j];
    while(x!=y)
      if(x>y)
        x=x-y;
        else
        y=y-x;
        if(x==1)
            nr++;
    }
     g<<nr;
    return 0;
}