#include <iostream>
#include <fstream>
#define Nmax 10001
using namespace std;

int v[Nmax];
ifstream f("fractii.in");
ofstream g("fractii.out");

int main()
{

    int n ;
    long long s = 0;
    f >> n;
    v[1] = 1;
    for (int i = 2 ; i<=n ; i++) v[i] = i - 1;
    for (int i = 2 ; i<=n ; i++) {
        s+=v[i];
        for(int j = 2*i ;j<=n; j+=i)
            v[j]-=v[i];
    }
    g << 2*s+1;
    return 0;
}