#include <iostream>
#include<fstream>
using namespace std;
fstream f("fractii.in",ios::in);
fstream g("fractii.out",ios::out);
unsigned long n;
unsigned long divizori(unsigned long n)
{
    unsigned long nrd=1,d;
    for(d=2;d<=n/2;d++)
        if(n%d==0)
            nrd++;
    return nrd;
}
int numar(unsigned long n)
{
    int nr=n;
    unsigned long i;
    for(i=2;i<=n;i++)
        if(divizori(i)>1)
            nr=nr+n-n/divizori(i);
        else
            nr=nr+n-n/i;
    return nr;
}
int main()
{   f>>n;
    g<<numar(n);
    f.close();
    g.close();
    cout << "Hello world!" << endl;
    return 0;
}