#include <bits/stdc++.h>
using namespace std;
bool check(long long n) {
  set<long long> s;
  while (n % 2 == 0) {
    s.insert(2);
    n = n / 2;
  }
  for (int i = 3; i <= sqrt(n); i = i + 2) {
    while (n % i == 0) {
      s.insert(i);
      n = n / i;
    }
  }
  if (n > 2) s.insert(n);
  if (s.size() == 2) return true;
  return false;
}
void solve() {
  long long a;
  cin >> a;
  long long c = 0;
  for (long long i = 1; i < a + 1; i++) {
    if (check(i)) c++;
  }
  cout << c;
}
int main() {
  int t = 1;
  while (t--) {
    solve();
  }
  return 0;
}
