#include <fstream>
#include <vector>
#include <algorithm>
#include <cctype>
#include <cmath>
#include <queue>
#include <cstring>
/*#include <iostream>
#define f cin
#define g cout*/
#define max(a,b) ((a>b) ? a : b)
#define min(a,b) ((a<b) ? a : b)
#define FORC(i,x,y,t) for (i=x;i<=y;i+=t)
#define FOR(i,x,t) for (i=1;i<=x;i+=t)
#define FORD(i,x,y,t) for (i=x;i>=y;i-=t)
#define LL long long
#define LiteraMica islower
#define LiteraMare isupper
#define Cifra isdigit
#define Gol(Vector,x) memset(Vector,x,sizeof(Vector))
using namespace std;
int N,i,P[1000003],j;
LL ans;
ifstream f("fractii.in");
ofstream g("fractii.out");
int main()
{
    f>>N;
    FOR(i,N,1) P[i]=i-1;
    FORC(i,2,N,1)
       {
           ans+=P[i];
           FORC(j,2*i,N,i) P[j]-=P[i];
       }
    g<<2*ans+1;
    f.close();
    g.close();
    return 0;
}