#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
#define rep(i, n) for (long long i = 0; i < (long long)(n); i++)
#define rrep(i,start,end) for (long long i = start;i >= (long long)(end);i--)
#define repn(i,end) for(long long i = 0; i <= (long long)(end); i++)
#define reps(i,start,end) for(long long i = start; i < (long long)(end); i++)
#define repsn(i,start,end) for(long long i = start; i <= (long long)(end); i++)
#define each(p,a) for(auto &p:a)
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef vector<long long> vll;
typedef vector<pair<long long ,long long>> vpll;
typedef vector<vector<long long>> vvll;
typedef set<ll> sll;
typedef map<long long , long long> mpll;
typedef pair<long long ,long long> pll;
typedef tuple<long long , long long , long long> tpl3;
#define LL(...) ll __VA_ARGS__; input(__VA_ARGS__)
#define LD(...) ld __VA_ARGS__; input(__VA_ARGS__)
#define Str(...) string __VA_ARGS__; input(__VA_ARGS__)
#define Ch(...) char __VA_ARGS__; input(__VA_ARGS__)
#define all(a)  (a).begin(),(a).end()
#define UNIQUE(v) v.erase( unique(v.begin(), v.end()), v.end() );
#define sz(x) (int)x.size()
// << std::fixed << std::setprecision(10)
const ll INF = 1LL << 60;
const ld EPS = 1e-9;
 
inline ll lfloor(ll x,ll m){return (x - ((x % m+ m)%m))/m;}
inline ll positive_mod(ll a,ll m){return (a % m + m)%m;}
inline ll popcnt(ull a){ return __builtin_popcountll(a);}
template<class T> bool chmin(T& a, T b){if(a > b){a = b;return true;}return false;}
template<class T> bool chmax(T& a, T b){if(a < b){a = b;return true;}return false;}
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::vector<T>&v){for(auto it=std::begin(v);it!=std::end(v);){os<<*it<<((++it)!=std::end(v)?" ":"");}return os;}
template<typename T1, typename T2>std::ostream &operator<< (std::ostream &os, std::pair<T1,T2> p){os << "{" << p.first << "," << p.second << "}";return os;}
template<class... T>void input(T&... a){(cin >> ... >> a);}
void print(){cout << endl;}
template<class T, class... Ts>void print(const T& a, const Ts&... b){cout << a;((cout << ' ' << b), ...);cout << endl;}
template<class T> void pspace(const T& a){ cout << a << ' ';}
void perr(){cerr << endl;}
template<class T, class... Ts>void perr(const T& a, const Ts&... b){cerr << a;((cerr << ' ' << b), ...);cerr << endl;}
void yes(bool i = true){ return print(i?"yes":"no"); }
void Yes(bool i = true){ return print(i?"Yes":"No"); }
void YES(bool i = true){ return print(i?"YES":"NO"); }
template <class T> vector<T> &operator++(vector<T> &v) {for(auto &e : v) e++;return v;}
template <class T> vector<T> operator++(vector<T> &v, signed) {auto res = v;for(auto &e : v) e++;return res;}
template <class T> vector<T> &operator--(vector<T> &v) {for(auto &e : v) e--;return v;}
template <class T> vector<T> operator--(vector<T> &v, signed) {auto res = v;for(auto &e : v) e--;return res;}
//grid探索用
vector<ll> _ta = {0,0,1,-1,1,1,-1,-1};
vector<ll> _yo = {1,-1,0,0,1,-1,1,-1};
bool isin(ll now_i,ll now_j,ll h,ll w){return (0<=now_i && now_i < h && 0 <= now_j && now_j < w);}
  
ll lpow(ll x,ll n){ll ans = 1;while(n >0){if(n & 1)ans *= x;x *= x;n >>= 1;}return ans;}
ll Modlpow(ll x,ll n,ll m){ll ans = 1;ll a = x%m;while(n >0){if(n & 1){ans *= a;ans%= m;}a *= a;a %= m;n >>= 1;}return ans;} 
const ll MOD9 = 998244353LL;
const ll MOD10 = 1000000007LL;

//https://drken1215.hatenablog.com/entry/2023/05/23/233000
// A^N mod M
template<class T> T pow_mod(T A, T N, T M) {
    T res = 1 % M;
    A %= M;
    while (N) {
        if (N & 1) res = (res * A) % M;
        A = (A * A) % M;
        N >>= 1;
    }
    return res;
}

bool MillerRabin(long long N, vector<long long> A) {
    long long s = 0, d = N - 1;
    while (d % 2 == 0) {
        ++s;
        d >>= 1;
    }
    for (auto a : A) {
        if (N <= a) return true;
        long long t, x = pow_mod<__int128_t>(a, d, N);
        if (x != 1) {
            for (t = 0; t < s; ++t) {
                if (x == N - 1) break;
                x = __int128_t(x) * x % N;
            }
            if (t == s) return false;
        }
    }
    return true;
}

bool is_prime(long long N) {
    if (N <= 1) return false;
    if (N == 2) return true;
    if (N % 2 == 0) return false;
    if (N < 4759123141LL)
        return MillerRabin(N, {2, 7, 61});
    else
        return MillerRabin(N, {2, 325, 9375, 28178, 450775, 9780504, 1795265022});
}
 
int main(){
  ios::sync_with_stdio(false);cin.tie(nullptr);
  LL(n);
  ll v = 1;
  ll cnt =0;
  reps(i,2,n){
    if(!is_prime(i))continue;
    if(n/v < i){
      break;
    }
    cnt++;
    v *= i;
  }
  cout << cnt << endl;
}