#ifdef MAIN 
bool __multi__ = 0;

namespace XK {

V<int> mu(int n) {
  V<int> mu(n + 1), primes;
  V<bool> not_prime(n + 1);
  primes.reserve(n);
  mu[1] = 1;
  for (int x = 2; x <= n; ++x) {
    if (!not_prime[x]) {
      primes.push_back(x);
      mu[x] = -1;
    }
    for (int p : primes) {
      if (x * p > n) break;
      not_prime[x * p] = true;
      if (x % p == 0) {
        mu[x * p] = 0;
        break;
      } else {
        mu[x * p] = -mu[x];
      }
    }
  }
  return mu;
}

  void solve() {
  	int N; in(N);
  	V<int> m = mu(N);
  	ll ans = 0;
  	rep(i, N) ans += m[i + 1];
  	out(ans);
  }
};

signed main() {ios::sync_with_stdio(0);cin.tie(0);fixed(cout).precision(12);int t = 1;if(__multi__) cin >> t;while(t --) XK::solve();}
#else
#include "cassert"
#include "cmath"
#include "cstdint"
#include "cstdio"
#include "cstdlib"
#include "cstring"
#include "algorithm"
#include "bitset"
#include "chrono"
#include "complex"
#include "deque"
#include "functional"
#include "iostream"
#include "limits"
#include "map"
#include "numeric"
#include "queue"
#include "random"
#include "set"
#include "sstream"
#include "string"
#include "unordered_map"
#include "unordered_set"
#include "utility"
#include "vector"
#include "array"
using namespace std;
#define int long long
using ll = long long;
using ull = unsigned long long;
const ll INF = 1ll << 60;
const ll LINF = 0x1fffffffffffffff;
const ll MINF = 0x7fffffffffff;
template <class A, class B> bool chmax(A& l, const B& r){ return r > l ? l = r, 1 : 0; }
template <class A, class B> bool chmin(A& l, const B& r){ return r < l ? l = r, 1 : 0; }
#define sz(x) ssize(x)
#define rep(i, a) for(ll i = 0; i < (a); i ++)
#define Rep(i, a, b) for(ll i = (a); i < (b); i ++)
#define rrep(i, a, b) for(ll i = (b); i --> (a); )
#define all(x) begin(x), end(x)
#define fst first
#define snd second
#define pb push_back
template<class T> using V = vector<T>;
template<class T, std::size_t N> using AR = array<T, N>;
namespace IO {
  template<class... Ts> void in(Ts&... t);
  [[maybe_unused]] void print(){}
  template<class T, class... Ts> void print(const T& t, const Ts&... ts);
  template<class... Ts> void out(const Ts&... ts){ print(ts...); cout << '\n'; }
  namespace IO{
      #define VOID(a) decltype(void(a))
      struct S{ S(){ cin.tie(nullptr)->sync_with_stdio(0); fixed(cout).precision(12); } }S;
      template<int I> struct P : P<I-1>{};
      template<> struct P<0>{};
      template<class T> void i(T& t){ i(t, P<3>{}); }
      void i(vector<bool>::reference t, P<3>){ int a; i(a); t = a; }
      template<class T> auto i(T& t, P<2>) -> VOID(cin >> t){ cin >> t; }
      template<class T> auto i(T& t, P<1>) -> VOID(begin(t)){ for(auto&& x : t) i(x); }
      template<class T, size_t... idx> void ituple(T& t, index_sequence<idx...>){ in(get<idx>(t)...); }
      template<class T> auto i(T& t, P<0>) -> VOID(tuple_size<T>{}){ ituple(t, make_index_sequence<tuple_size<T>::value>{}); }
      template<class T> void o(const T& t){ o(t, P<4>{}); }
      template<size_t N> void o(const char (&t)[N], P<4>){ cout << t; }
      template<class T, size_t N> void o(const T (&t)[N], P<3>){ o(t[0]); for(size_t i = 1; i < N; i++){ o(' '); o(t[i]); } }
      template<class T> auto o(const T& t, P<2>) -> VOID(cout << t){ cout << t; }
      template<class T> auto o(const T& t, P<1>) -> VOID(begin(t)){ bool first = 1; for(auto&& x : t) { if(first) first = 0; else o(' '); o(x); } }
      template<class T, size_t... idx> void otuple(const T& t, index_sequence<idx...>){ print(get<idx>(t)...); }
      template<class T> auto o(T& t, P<0>) -> VOID(tuple_size<T>{}){ otuple(t, make_index_sequence<tuple_size<T>::value>{}); }
      #undef VOID
  }
  template<class... Ts> void in(Ts&... t){ (IO::i(t), ...); }
  template<class T, class... Ts> void print(const T& t, const Ts&... ts){ IO::o(t); (IO::o((cout << ' ', ts)), ...); }
  #undef unpack
  constexpr ll debug_const(ll judge, ll debug) {
  #ifdef DEBUG
      return debug;
  #else
      return judge;
  #endif
  }
  #ifdef DEBUG
  ll __lg(ull x){ return 63 - __builtin_clzll(x); }
  #define debug(...) { print(#__VA_ARGS__); print(":"); out(__VA_ARGS__); }
  #else
  #define debug(...) void(0)
  #endif
  #define dbg debug
} using namespace IO;
#define MAIN
#include __FILE__
#endif