//#include <iostream>
#include <fstream>

using namespace std;
ifstream cin("fractii.in");
ofstream cout("fractii.out");
int n, nr=1;

int cmmdc(int a, int b)
{
    int r=a%b;
    while(r)
    {
        a=b;
        b=r;
        r=a%b;
    }
    return b;
}

int main()
{
    cin>>n;
    for(int i=1; i<n; i++)
    {
        for(int j=i+1; j<=n; j++)
        {
            if(cmmdc(i, j)==1)
            {
                nr+=2;
            }
        }
    }
    cout<<nr;
    return 0;
}