#include <iostream>
#include<fstream>
using namespace std;
FILE *f;
FILE *g;
f = fopen("adunare.in","r");
g = fopen("adunare.out","w");
unsigned long n;
unsigned long cmmdc(unsigned long a, unsigned long b)
{
    unsigned long r;
    while(b!=0)
    {
        r=a%b;
        a=b;
        b=r;
    }
    return a;
}
int numar(unsigned long n)
{
    int nr=2*(n-1)-1+2*(n-n/2);
    unsigned long i,j;
    for(i=3;i<n;i++)
    for(j=i+1;j<=n;j++)
        if(cmmdc(i,j)==1)
            nr=nr+2;
    return nr;
}
int main()
{
    fscanf(f,"%lu",&n);
    fprintf(g,"%i\n",numar(n));
    fclose(g);
    fclose(f);
    return 0;
}