#include<iostream>
#include<vector>
#include<iomanip>
#include<algorithm>
#include<numeric>
#include<queue>
#include<unordered_set>
#include<set>
#include<map>
#include<cmath>
using namespace std;

#include<atcoder/all>
using namespace atcoder;

//{{{
#pragma GCC target("avx")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
struct _MyInit{
  _MyInit(){
    std::cin.tie(0); ios::sync_with_stdio(false);
    cout<<fixed<<setprecision(20);
  };
}_myinit;

using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using ull = unsigned long long;
using ll = long long;
using vll = vector<ll>;
using vvll = vector<vll>;
using vvvll = vector<vvll>;
using vs = vector<string>;
using pii = pair<int,int>;
using vpii = vector<pii>;
using vvpii = vector<vpii>;
using pll = pair<ll,ll>;
using vpll = vector<pll>;
using vvpll = vector<vpll>;
template<typename T> using pqueue = priority_queue<T>;
template<typename T> using pqueue_g = priority_queue<T,vector<T>,greater<T>>;

#define endl ('\n')

#define all(v) (v).begin(),(v).end()
#define rall(v) (v).rbegin(),(v).rend()
#define UNIQ(v) (v).erase(unique((v).begin(),(v).end()),(v).end())

#define _overload4(_1,_2,_3,_4,name,...) name
#define __REP(i,s,e,d) for(ll i=ll(s);i<ll(e);i+=(d))
#define _REP(i,s,e) for(ll i=ll(s);i<ll(e);i++)
#define REP(i,n) _REP(i,0,n)
#define rep(...) _overload4(__VA_ARGS__,__REP,_REP,REP,)(__VA_ARGS__)
#define reps(i,n) _REP(i,1,n+1)
#define __RREP(i,s,e,d) for(ll i=ll(s);i>=ll(e);i-=d)
#define _RREP(i,s,e) for(ll i=ll(s);i>=ll(e);i--)
#define RREP(i,n) _RREP(i,n-1,0)
#define rrep(...) _overload4(__VA_ARGS__,__RREP,_RREP,RREP,)(__VA_ARGS__)
#define rreps(i,n) _RREP(i,n,1)

template<class T>inline bool chmax(T &a,const T &b){if(a<b){a=b;return 1;}return 0;}
template<class T>inline bool chmin(T &a,const T &b){if(b<a){a=b;return 1;}return 0;}
//}}}

int main(){
  ll n; cin >> n;

  vector<bool> a(n,true);
  a[0] = false;
  for(ll i=2;i*i<=n;i++){
    ll I = i*i;
    for(ll j=1;j*I<=n;j++){
      a[j*I]=false;
    }
  }

  ll ans = 0;
  for(ll k=1;k<=n;k++){
    if(a[k]){
      ll b=sqrt(n/k);
      ans += b*b;
    }
  }

  cout << ans << endl;

  return 0;
}