#pragma region template
#pragma GCC optimize("Ofast")
#include <bits/stdc++.h>
using namespace std;

using ll = long long;
using ld = long double;
using vi = vector<int>;
using vll = vector<ll>;
using pi = pair<int, int>;
using pll = pair<ll, ll>;

#define overload2(a, b, c, ...) c
#define overload3(a, b, c, d, ...) d
#define overload4(a, b, c, d, e, ...) e
#define overload5(a, b, c, d, e, f, ...) f

#define TYPE1(T) template <typename T>
#define TYPE2(T, U) template <typename T, typename U>
#define TYPE(...) overload2(__VA_ARGS__, TYPE2, TYPE1)(__VA_ARGS__)
#define TYPES1(T) template <typename... T>
#define TYPES2(H, T) template <typename H, typename... T>
#define TYPES(...) overload2(__VA_ARGS__, TYPES2, TYPES1)(__VA_ARGS__)

#define REP4(i, s, n, d) for (int i = (s); i < (n); i += (d))
#define REP3(i, s, n) REP4(i, s, n, 1)
#define REP2(i, n) REP3(i, 0, n)
#define REP1(n) REP2(tomato, n)
#define REP(...) overload4(__VA_ARGS__, REP4, REP3, REP2, REP1)(__VA_ARGS__)

#define RREP4(i, n, s, d) for (int i = (n)-1; i >= (s); i -= (d))
#define RREP3(i, n, s) RREP4(i, n, s, 1)
#define RREP2(i, n) RREP3(i, n, 0)
#define RREP1(n) RREP2(tomato, n)
#define RREP(...) overload4(__VA_ARGS__, RREP4, RREP3, RREP2, RREP1)(__VA_ARGS__)

#define FOR4(a, b, c, d, v) for (auto [a, b, c, d] : v)
#define FOR3(a, b, c, v) for (auto [a, b, c] : v)
#define FOR2(a, b, v) for (auto [a, b] : v)
#define FOR1(a, v) for (auto a : v)
#define FOR(...) overload5(__VA_ARGS__, FOR4, FOR3, FOR2, FOR1)(__VA_ARGS__)

#define AFOR4(a, b, c, d, v) for (auto &[a, b, c, d] : v)
#define AFOR3(a, b, c, v) for (auto &[a, b, c] : v)
#define AFOR2(a, b, v) for (auto &[a, b] : v)
#define AFOR1(a, v) for (auto &a : v)
#define AFOR(...) overload5(__VA_ARGS__, AFOR4, AFOR3, AFOR2, AFOR1)(__VA_ARGS__)

#define CFOR4(a, b, c, d, v) for (const auto &[a, b, c, d] : v)
#define CFOR3(a, b, c, v) for (const auto &[a, b, c] : v)
#define CFOR2(a, b, v) for (const auto &[a, b] : v)
#define CFOR1(a, v) for (const auto &a : v)
#define CFOR(...) overload5(__VA_ARGS__, CFOR4, CFOR3, CFOR2, CFOR1)(__VA_ARGS__)

#define PFOR(v) for (bool f = true; (f ? exchange(f, false) : next_permutation(ALL(v)));)

#define ALL(v) v.begin(), v.end()
#define RALL(v) v.rbegin(), v.rend()
#define SORT(v) sort(ALL(v))
#define RSORT(v) sort(RALL(v))
#define REVERSE(v) reverse(ALL(v))
#define UNIQUE(v) SORT(v), v.erase(unique(ALL(v)), v.end())
#define SZ(v) int(v.size())
#define MAX(v) *max_element(ALL(v))
#define MIN(v) *min_element(ALL(v))
template <typename T>
conditional_t<is_same_v<T, int>, ll, T> SUM(const vector<T> &v)
{
  return accumulate(ALL(v), conditional_t<is_same_v<T, int>, ll, T>(0));
}

TYPES(T)
void input(T &...a) { (cin >> ... >> a); }
#define DECLARE(T, ...) \
  T __VA_ARGS__;        \
  input(__VA_ARGS__);
#define INT(...) DECLARE(int, __VA_ARGS__)
#define STR(...) DECLARE(string, __VA_ARGS__)
#define LL(...) DECLARE(long long, __VA_ARGS__)
#define CHR(...) DECLARE(char, __VA_ARGS__)
#define DBL(...) DECLARE(double, __VA_ARGS__)
#define VI(n, v) \
  vi v(n);       \
  cin >> v;
#define VLL(n, v) \
  vll v(n);       \
  cin >> v;
#define VS(n, s)       \
  vector<string> s(n); \
  cin >> s;

TYPE(T)
istream &operator>>(istream &is, vector<T> &v)
{
  for (auto &a : v)
    cin >> a;
  return is;
}
TYPE(T)
ostream &operator<<(ostream &os, const vector<T> &v)
{
  if (&os == &cerr)
    os << "[";
  REP(i, v.size())
  {
    os << v[i];
    if (i + 1 < v.size())
      os << (&os == &cerr ? "," : " ");
  }
  if (&os == &cerr)
    os << "]";
  return os;
}
TYPE(T, S)
istream &operator>>(istream &is, pair<T, S> &p)
{
  cin >> p.first >> p.second;
  return is;
}

#ifdef __DEBUG
#include <debug>
#else
#define debug(...) void(0)
#endif

void print()
{
  cout << '\n';
}
TYPES(T, Ts)
void print(const T &a, const Ts &...b)
{
  cout << a;
  (cout << ... << (cout << ' ', b));
  cout << '\n';
}

TYPE(T)
using pq = priority_queue<T>;
TYPE(T)
using pqg = priority_queue<T, vector<T>, greater<T>>;
TYPE(T)
T pick(queue<T> &que)
{
  assert(que.size());
  T a = que.front();
  que.pop();
  return a;
}
TYPE(T)
T pick(pq<T> &que)
{
  assert(que.size());
  T a = que.top();
  que.pop();
  return a;
}
TYPE(T)
T pick(pqg<T> &que)
{
  assert(que.size());
  T a = que.top();
  que.pop();
  return a;
}
TYPE(T)
T pick(stack<T> &sta)
{
  assert(sta.size());
  T a = sta.top();
  sta.pop();
  return a;
}
TYPE(T)
void clear(T &v) { v = decltype(v)(); }

string YES(bool f = true) { return (f ? "YES" : "NO"); }
string Yes(bool f = true) { return (f ? "Yes" : "No"); }
string yes(bool f = true) { return (f ? "yes" : "no"); }

constexpr int INF = 1e9 + 7;
constexpr ll LINF = ll(1e18) + 7;
constexpr ld EPS = 1e-10;

vi iota(int n)
{
  vi a(n);
  iota(ALL(a), 0);
  return a;
}
TYPE(T)
vector<pair<T, int>> query_sort(const vector<T> &v)
{
  vector<pair<T, int>> res(v.size());
  REP(i, v.size())
  res[i] = {v[i], i};
  SORT(res);
  return res;
}
TYPE(T)
void add(vector<T> &v, T a = 1)
{
  AFOR(p, v)
  p += a;
}
TYPE(T)
T rev(T a)
{
  REVERSE(a);
  return a;
}
TYPE(T)
void fin(T a)
{
  cout << a << '\n';
  exit(0);
}
TYPE(T)
bool chmax(T &a, T b) { return (a < b && (a = b, true)); }
TYPE(T)
bool chmin(T &a, T b) { return (a > b && (a = b, true)); }
TYPES(T, Ns)
auto make_vector(T x, int n, Ns... ns)
{
  if constexpr (sizeof...(ns) == 0)
    return vector<T>(n, x);
  else
    return vector(n, make_vector<T>(x, ns...));
}
bool in(const ll S, const int a) { return (S >> a) & 1; }
int popcount(const ll S) { return __builtin_popcountll(S); }
int digit(char c) { return (c >= '0' and c <= '9' ? c - '0' : -1); }
ll sqrtll(ll a)
{
  for (ll b = sqrt(a); b * b <= a; b++)
    if (b * b == a)
      return b;
  for (ll b = sqrt(a); b >= 0 and b * b >= a; b--)
    if (b * b == a)
      return b;
  return -1;
}
#pragma endregion template

int main()
{
  ios::sync_with_stdio(false);
  cin.tie(nullptr);

  LL(n);
  int res = 0;
  int lst = n - 1;
  while (lst >= 2)
  {
    // lst を試す
    // (n-1)/a >= lst を満たす a
    int a = (n - 1) / lst - 1;
    while (!a || (n - 1) / (a + 1) >= lst)
      a++;

    int r = (n - 1) / a;
    int l = (n + 1 + a) / (a + 1);
    chmin(r, lst);
    debug(a, l, r);
    if (l > r)
    {
      lst--;
      continue;
    }
    debug(n, lst, a, l, r);
    // [l,r] を追加
    res += r - l + 1;
    lst = l - 1;
  }
  cout << res << '\n';
}