#include <bits/stdc++.h>
using namespace std;
int pr(long long n) {
  if ((n == 2) || (n == 3) || (n == 5) || (n == 7) ||
      ((((n % 6) == 1) || ((n % 6) == 5)) && (n % 7 != 0) && (n % 5 != 0)))
    return 1;
  else
    return 0;
}
int main() {
  long long n, i, c = 0, j, t, k, d = 0;
  cin >> n;
  if (n < 6) {
    cout << 0;
    return 0;
  }
  for (i = 6; i <= n; i++) {
    c = 0;
    j = 2;
    t = 1;
    k = i;
    while (k != 1) {
      if (k % j == 0) {
        if (j != t) {
          c++;
          t = j;
        }
        k = k / j;
      } else
        j++;
    }
    if (c == 2) {
      d++;
    }
  }
  cout << d;
  return 0;
}
