#include <bits/stdc++.h>

#define REP_(i, a_, b_, a, b, ...) for (int i = (a), END_##i = (b); i < END_##i; ++i)
#define REP(i, ...) REP_(i, __VA_ARGS__, __VA_ARGS__, 0, __VA_ARGS__)
#define ALL(x) std::begin(x), std::end(x)
using Int = long long;
using Uint = unsigned long long;
using Real = long double;

template<typename T, typename U>
inline bool chmax(T &a, U b) { return a < b and ((a = b), true); }
template<typename T, typename U>
inline bool chmin(T &a, U b) { return a > b and ((a = b), true); }
template<typename T>
constexpr T kBigVal = std::numeric_limits<T>::max() / 2;
#if __cplusplus < 202002L
template<typename T>
inline int ssize(const T &a) { return (int) a.size(); }
#endif

struct CastInput {
  template<typename T>
  operator T() const {
    T x;
    assert(std::cin >> x);
    return x;
  }
  struct Sized {
    int n;
    template<typename T>
    operator T() const {
      T xs(n);
      for (auto &x: xs) assert(std::cin >> x);
      return xs;
    }
  };
  Sized operator()(int n) const { return {n}; }
} in;

template<typename Container>
std::ostream &print_seq(const Container &seq,
                        const char *sep = " ",
                        const char *ends = "\n",
                        std::ostream &os = std::cout) {
  const auto itl = std::begin(seq), itr = std::end(seq);
  for (auto it = itl; it != itr; ++it) {
    if (it != itl) os << sep;
    os << *it;
  }
  return os << ends;
}

template<typename T>
inline std::ostream &print_one(const T &x, char endc) {
  if constexpr (std::is_same<T, bool>::value) {
    return std::cout << (x ? "Yes" : "No") << endc;
  } else {
    return std::cout << x << endc;
  }
}
template<typename T>
inline std::ostream &print(const T &x) { return print_one(x, '\n'); }
template<typename T, typename... Ts>
std::ostream &print(const T &head, Ts... tail) {
  return print_one(head, ' '), print(tail...);
}
inline std::ostream &print() { return std::cout << '\n'; }

void init_(bool interactive = false) {
  std::ios::sync_with_stdio(false);
  if (not interactive) std::cin.tie(nullptr);
  std::cout << std::fixed << std::setprecision(18);
}

void exit_() {
#ifdef MY_DEBUG
  std::string unused;
  assert(not(std::cin >> unused));  // No input is left behind.
#endif
  std::cout.flush(), std::cerr.flush(), std::_Exit(0);
}

inline void init_test_case(int t, int T) {
#ifdef MY_DEBUG
  if (T > 1) {
    std::cerr << "\033[35m=== case " << t << " of " << T << " ===\033[0m"
              << std::endl;
  }
#endif
}

#ifdef MY_DEBUG
#include "debug_dump.hpp"
#include "backward.hpp"
backward::SignalHandling kSignalHandling;
#else
#define DUMP(...)
#define cerr if(false)cerr
#endif

using namespace std;

// O(n) sieve
struct PrimeSieve {
  std::vector<int> spf;  // smallest prime factors table.
  std::vector<int> primes;

  explicit PrimeSieve(int n) : spf(n + 1) {
    for (int i = 2; i <= n; ++i) {
      if (spf[i] == 0) {
        spf[i] = i;
        primes.push_back(i);
      }
      for (const auto &p: primes) {
        if (i * p > n) break;
        spf[i * p] = p;
        if (i % p == 0) break;
      }
    }
  }

  inline bool is_prime(int n) const { return spf[n] == n; }

  auto factorize(int n) const {
    assert(0 < n and n < int(spf.size()));
    std::vector<std::pair<Int, int>> res;
    while (n > 1) {
      const int p = spf[n];
      int count = 0;
      do {
        n /= p;
        ++count;
      } while (n % p == 0);
      res.emplace_back(p, count);
    }
    return res;
  }
};

// Enumerates divisors from prime factorization.
// O(d(n)) + sorting
std::vector<Int> enumerate_divisors(
    const std::vector<std::pair<Int, int>> &fac) {
  std::vector<Int> res = {1};
  for (auto [p, k]: fac) {
    int sz = res.size();
    for (int i = 0; i < sz; ++i) {
      Int pp = 1;
      for (int j = 0; j < k; ++j) {
        pp *= p;
        res.push_back(res[i] * pp);
      }
    }
  }
  //std::sort(res.begin(), res.end());
  return res;
}

auto solve() {
  Int N = in;
  vector<int> fp(N + 10, -1);
  for (int i = 1; i <= N; ++i) {
    Int i2 = Int(i) * i;
    if (i2 > N) break;
    for (Int j = 1;; ++j) {
      Int x = j * i2;
      if (x > N) break;
      fp[x] = j;
    }
  }
  vector<int> cnt(N + 10, 0);
  for (int i = 1; i <= N; ++i) {
    ++cnt[fp[i]];
  }
  Int ans = 0;
  for (int i = 1; i <= N; ++i) {
    ans += Int(cnt[i]) * cnt[i];
  }
  print(ans);
}

int main() {
  init_();
  const int T = 1;//in;
  REP(t, T) {
    init_test_case(t, T);
    (solve());
  }
  exit_();
}