#include <fstream>
#include <cmath>
using namespace std;
bool prime(int i,int j)
{
   if(i%2==0 and j%2==0) return 1;
   int d=3,e;
   if(i%j==0 or j%i==0) return 1;
   if(i<j)
        e=j;
   else
        e=i;
   e=sqrt(e);
   while(d<=e)
   {
       if(i%d==0 and j%d==0) return 1;
       d+=2;
   }
   return 0;
}
int main()
{
    ifstream f("fractii.in");
    ofstream g("fractii.out");
    int n,i,j;
    unsigned long long s;
    f>>n;
    s=n+n-1;
    for(i=2;i<=n;i++)
    {
        if(i%2==0)
        for(j=3;j<=n;j+=2)
        {
            if(prime(i,j)==0) s+=1;
        }
        if(i%2==1)
        {
            for(j=2;j<=n;j++)
            if(prime(i,j)==0) s+=1;
        }
    }
    g<<s;
    f.close();
    g.close();
    return 0;
}