#include <iostream.h>
#include <fstream.h>
void citire(long int a[1000][1000],unsigned long int n)
{
     unsigned long int k=0;
     for(int i=0;i<=999;i++)
     for(int j=0;j<=999;j++)
     {
     a[i][j]=k;
     k++;
     }
}
void ciur(long int a[1000][1000],unsigned long int n)
{
     int p=2;
     do
     {
         for(int i=0;i<=999;i++)
         for(int j=0;j<=999;j++)
         if(a[i][j]/p>1&&a[i][j]%p==0)
         a[i][j]==0;
         }while(p*p<n);
}
         
int numere(long int a[1000][1000])
{
     unsigned long int nr=0;
     for(int i=0;i<=999;i++)
     for(int j=0;j<=999;j++)
     if(a[i][j]!=1&&a[i][j]!=0)
     nr++;
     return nr;
}
int fractii(unsigned long int nr,unsigned long int n)
{
    unsigned long int x=0;
    x+=2*n-1;
    for(unsigned long int i=2;i<nr;i++)
    x+=2*nr-2*i;
    return x;
}
int main()
{
    long int a[1000][1000];
    unsigned long int n,nr,k,x;
    fstream g("fractii.in",ios::in);
    fstream h("fractii.out",ios::out);
    g>>n;
    citire(a,n);
    ciur(a,n);
    nr=numere(a);
    x=fractii(nr,n);
    h<<x;
    return 0;
}