#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define ar array
#define sim template < class c
#define ris return * this
#define dor > debug & operator <<
#define eni(x) sim > typename \
  enable_if<sizeof dud<c>(0) x 1, debug&>::type operator<<(c i) {
sim > struct rge { c b, e; };
sim > rge<c> range(c i, c j) { return rge<c>{i, j}; }
sim > auto dud(c* x) -> decltype(cerr << *x, 0);
sim > char dud(...);
struct debug {
#ifdef LOCAL
~debug() { cerr << endl; }
eni(!=) cerr << boolalpha << i; ris; }
eni(==) ris << range(begin(i), end(i)); }
sim, class b dor(pair < b, c > d) {
  ris << "(" << d.first << ", " << d.second << ")";
}
sim dor(rge<c> d) {
  *this << "[";
  for (auto it = d.b; it != d.e; ++it)
    *this << ", " + 2 * (it == d.b) << *it;
  ris << "]";
}
#else
sim dor(const c&) { ris; }
#endif
};
#define imie(...) " [" << #__VA_ARGS__ ": " << (__VA_ARGS__) << "] "

int n,rasp[1000005];

int main()
{
    cin >> n;
    for(int i=1;i<=n;i++){
        rasp[i]=i-1;
        debug() << range(rasp+1, rasp+n+1);
    }
    for(int i=2;i<=n;i++){
        for(int j=2*i;j<=n;j+=i){
            rasp[j]-=rasp[i];
        }
    }
    debug() << range(rasp+1, rasp+n+1);
    ll sum=0;
    for(int i=1;i<=n;i++){
        sum+=rasp[i];
        debug() << imie(sum);
    }
    
    cout<<sum*2+1;
    
    return 0;
}