#include <fstream>

using namespace std;
ifstream fin("fractii.in");
ofstream fout("fractii.out");

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

int main()
{
    int N;
    long long nr=0;
    fin>>N;
    nr=2*N-1;
    for(int i=2;i<N;i++)
    {
        if(i%2==0)
        {
            for(int j=i+1;j<=N;j+=2)if(cmmdc(i,j)==1)nr+=2;
        }else for(int j=i+1;j<=N;j++)if(cmmdc(i,j)==1)nr+=2;
    }
    fout<<nr;
    return 0;
}