#include <iostream>
#include <fstream>
#define NMAX 1000001

using namespace std;

ifstream in("fractii.in");
ofstream out("fractii.out");

int n;
int a[NMAX];

void afisare()
{
    for(int i=1;i<=n;i++)
        cout<<a[i]<<" ";
        cout<<'\n';
}

int main()
{
    in>>n;
    in.close();
    a[0] = 1;
    for(int i=1;i<=n;i++)
        a[i] = i-1;
    for(int i = 2;i<=n;i++)
    {
        for(int k = 2*i;k<=n;k+=i)
            a[k]-=a[i];
    }
    long long int fractii = 0;
    for(int i =1;i<=n;i++)
        fractii+=a[i];
    fractii = fractii*2+1;
    out<<fractii;
    return 0;
}