#line 2 "/home/snow/competitive-programming/competitive-programming-library/snow/template.hpp"
#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#include <bits/stdc++.h>

constexpr long long INF = 1LL << 60;
constexpr long double PI = 3.141592653589;

#define rep(i, n) for (ll i = 0; i < (n); ++i)
#define rep1(i, n) for (ll i = 1; i <= (n); ++i)
#define rrep(i, n) for (ll i = (n - 1); i >= 0; --i)
#define ALL(obj) (obj).begin(), (obj).end()
#define RALL(obj) (obj).rbegin(), (obj).rend()
#define pb push_back
#define to_s to_string
#define len(v) (ll) v.size()
#define debug(x) cout << #x << ": " << (x) << '\n'

using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<ll, ll> P;
typedef tuple<ll, ll, ll> tpl;

template <typename T = ll>
using vec = vector<T>;

template <typename T = ll>
using vec2 = vector<vector<T>>;

template <typename T = ll>
using vec3 = vector<vector<vector<T>>>;

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

template < typename T >
inline bool chmin(T &a, const T &b) {
    if (b < a) {
        a = b;
        return 1;
    }
    return 0;
}
#line 4 "/home/snow/competitive-programming/competitive-programming-library/snow/io/setup.hpp"

namespace snow{

struct IoSetup {
    IoSetup() {
        std::cin.tie(nullptr);
        std::ios::sync_with_stdio(false);
        std::cout << std::fixed << std::setprecision(10);
    }
} iosetup;

} // namespace snow
#line 5 "/home/snow/competitive-programming/competitive-programming-library/snow/io/helper.hpp"

template< typename T1, typename T2 >
std::ostream &operator << (std::ostream &os, const std::pair< T1, T2 > &p) {
    os << p.first << " " << p.second;
    return os;
}

template< typename T1, typename T2 >
std::istream &operator >> (std::istream &is, std::pair< T1, T2 > &p) {
    is >> p.first >> p.second;
    return is;
}

template< typename T1, typename T2, typename T3 >
std::ostream &operator << (std::ostream &os, const std::tuple< T1, T2, T3 > &t) {
    auto &[a, b, c] = t;
    os << a << " " << b << " " << c;
    return os;
}

template< typename T1, typename T2, typename T3 >
std::istream &operator >> (std::istream &is, std::tuple< T1, T2, T3 > &t) {
    auto &[a, b, c] = t;
    is >> a >> b >> c;
    return is;
}

template< typename T >
std::ostream &operator << (std::ostream &os, const std::vector< T > &v){
    for (int i = 0; i < (int)v.size(); ++i) {
        os << v[i] << (i + 1 != v.size() ? " " : "");
    }
    return os;
}

template< typename T >
std::istream &operator >>  (std::istream &is, std::vector< T > &v){
    for(T &in : v) is >> in;
    return is;
}

template< typename T >
std::ostream &operator << (std::ostream &os, const std::set< T > &st){
    int ct = 0;
    for(auto& s : st) os << s << (++ct != (int)st.size() ? " " : "");
    return os;
}

template<class... T>
void input(T&... a){
    (std::cin >> ... >> a);
}

void print() {
    std::cout << '\n';
}
template<class T, class... Ts>
void print(const T& a, const Ts&... b){
    std::cout << a;
    (std::cout << ... << (std::cout << ' ', b));
    std::cout << '\n';
}

int drop() {
    std::cout << '\n';
    exit(0);
}
template<class T, class... Ts>
int drop(const T& a, const Ts&... b){
    std::cout << a;
    (std::cout << ... << (std::cout << ' ', b));
    std::cout << '\n';
    exit(0);
}
#line 4 "main.cpp"
using namespace snow;

// #include "snow/algorithm/binary-search.hpp"

// #include "atcoder/modint"
// using namespace atcoder;
// using mint = modint1000000007;

#line 2 "/home/snow/competitive-programming/competitive-programming-library/snow/math/sieve.hpp"

#line 7 "/home/snow/competitive-programming/competitive-programming-library/snow/math/sieve.hpp"

namespace snow {

struct Sieve {
    public:
        Sieve(int n) : _n(n + 1), _sieve(_n){
            std::iota(_sieve.begin(), _sieve.end(), 0);
            for(int i = 2; i * i <= n; ++i){
                if(_sieve[i] < i) continue;
                for(int j = i * i; j <= n; j += i) if(_sieve[j] == j) _sieve[j] = i;
            }
        }

        std::map<int, int> factorize(int x){
            std::map<int, int> res;
            while(x != 1){
                res[_sieve[x]]++;
                x /= _sieve[x];
            }
            return res;
        }

        std::vector<int> enumerate_primes() {
            std::vector<int> primes;
            for(int i = 2; i < (int)_sieve.size(); ++i) {
                if(_sieve[i] == i) primes.emplace_back(i);
            }
            return primes;
        }

        bool isprime(int x){
            if(x == 0 or x == 1) return 0;
            return _sieve[x] == x;
        }

    protected:
        int _n;
        std::vector<int> _sieve;
};

} // namespace snow
#line 13 "main.cpp"


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

    vec<> sqfree(ll(5e7) + 10);
    for (ll x = 2; x * x <= 5e7; ++x){
        ll sq = x * x;
        for(ll j = sq; j <= 5e7; j += sq) sqfree[j] = true;
    }

    ll ans = 0;
    for(ll k = 1; k <= N; ++k) if(!sqfree[k]){
        ll r = sqrt(N / k);
        ans += r * r;
    }
    print(ans);

    return 0;
}