#include <bits/stdc++.h>
using namespace std;
int divisor(int num);
bool check_prime(int num);
int divisors[10000];
int main() {
  int n, i, j, count = 0, ans = 0;
  cin >> n;
  while (n >= 1) {
    j = divisor(n);
    for (i = 0; i < j; i++) {
      if (check_prime(divisors[i])) {
        count++;
      }
    }
    if (count == 2) {
      ans++;
    }
    count = 0;
    n--;
  }
  cout << ans;
  return 0;
}
int divisor(int num) {
  int i, j = 0;
  for (i = 2; i * i < num; i++) {
    if (num % i == 0) {
      divisors[j++] = i;
      divisors[j++] = num / i;
    }
  }
  if (i * i == num) divisors[j++] = i;
  return j;
}
bool check_prime(int num) {
  if (num == 2) return 1;
  if (num % 2 == 0) return 0;
  for (int i = 3; i * i <= num; i = i + 2) {
    if (num % i == 0) return 0;
  }
  return 1;
}
