#include <fstream>
using namespace std;
ifstream cin("fractii.in");
ofstream cout("fractii.out");
int v[1000005];
int main ()
{
    long long k = 0;
    int n,m,j,i;
    cin >> n;
    cin.close();
    for(i=2;i<=n;i++){
    v[i] = i - 1 ;}
    for(i=2;i<=n;i++){
        for(j=i+i;j<=n;j++)
        v[j] = v[j] - v[i] ;
        k=k+v[i];}
    cout<< 2*k+1;
    cout.close();
    return 0;
}