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

ifstream f("fractii.in");
ofstream g("fractii.out");

int cmmdc(int a, int b)
{
    int r;
    while(b)
    {
        r=a%b;
        a=b;
        b=r;
    }
    if(a==1)
        return 1;
    else
        return 0;
}

int main()
{
    int i,j,nr,n,r=0;
    f>>n;
    nr=2*n-1;
    j=1;
    for(i=2;i<=n-1;i++)
    {
        j++;
        if(cmmdc(i,j)==1)
            r++;
        if(j==n)
            j=1;
    }
    g<<nr+2*r;
    return 0;
}