#include <iostream>
#include <fstream>

using namespace std;

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

int main()
{
    int n,x,y;
    long long suma=0;
    f>>n;
    int v[n];
    for(x=1 ; x<=n ; x++)
        v[x]=x-1;

    for(x=2 ; x<=n ; x++ )
    {

        for(y=x*2 ; y<=n ; y+=x)
         v[y]=v[y]-v[x];
         suma=suma+v[x];


    }
    g<<suma*2+1;

    return 0;
}