#include <iostream>
#include <fstream>
using namespace std;
ifstream f("fractii.in");
ofstream g("fractii.out");
unsigned int Indicatorul_Euler(unsigned int n)
{
    unsigned int i,euler=n;
    if(n%2==0){
        euler -= euler/2;
        while(n%2==0)       n/=2;}

    for(i=3; i*i<=n; i+=2)
    {
        if(n%i==0){
            euler -= euler/i;
            while(n%i==0)    n/=i;}}
    if(n>1)
        euler -= euler/n;
    return euler;
}


int main()
{
    unsigned int n;
    long long s=0;
    f>>n;
    while (n!=1)
    {s+=Indicatorul_Euler(n);n--;}
    s+=s+1;
    g<<s;
    return 0;
}