#include <iostream>
#include <fstream>
using namespace std;

 ifstream f("fractii.in");
 ofstream g("fractii.out");
int v[10000];
int main()
{int i,j;
    long long nr = 0;
    int n;
    f >> n;

    for( i= 2; i <= n; i++)
        v[i] = i-1;

    for(i = 1; i <= n-i; i++)
        for( j= i+1; j <= n; j+=i)
            v[j] -= v[i];

    for( i = 2; i <= n; i++)
        nr += v[i];

    g << nr*2+1;

}