#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
  #include "settings/debug.cpp"
  #define _GLIBCXX_DEBUG
#else
  #define Debug(...) void(0)
#endif
#define rep(i, n) for (int i = 0; i < (n); ++i)
using ll = long long;
using ull = unsigned long long;

int main() {
  vector<int> primes = { 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47 };
  ll n;
  cin >> n;
  ll ans = 0, cnt = 1;
  for (int p : primes) {
    if (cnt * p > n) break;
    ans++;
    cnt *= p;
  }
  cout << ans << endl;
  return 0;
}