#include <iostream>
#include <fstream>

using namespace std;

int cmmdc(int a, int b)
{
    if(!b)
        return a;
    return cmmdc(b, a % b);
}

int main()
{
    ifstream f("fractii.in");
    ofstream g("fractii.out");
    int N, P, Q, contor = 0;
    f >> N;
    for(P = 1; P <= N/2; P++)
        for(Q = 1; Q <= N/2; Q++)
           if(cmmdc(P, Q) ==1 )
              contor++;
    g << contor*2;
    return 0;
}