#include <iostream>
#include <fstream>
using namespace std;
long long int cmmdc(long long int a, long long int b){
    if (b==0) return a;
    return cmmdc(b, a%b);
}
int main()
{
    ifstream fin;
    fin.open("fractii.in");
    long long int n;
    fin >> n;
    long long int counter = 0;
    for (long long int p = 1; p<n+1; p++){
        for (long long int q = 1; q<p+1; q++){
            if (cmmdc(p, q) == 1) counter++;
        }
    }
    ofstream fout;
    fout.open("fractii.out");
    fout << (counter*2-1);
    return 0;
}