use proconio::input;

fn solve() -> i32 {
  input! {
    n: usize,
  }
  let mut t = vec![1; n + 1];
  t[0] = 0;
  let mut p = vec![true; n + 1];
  p[0] = false;
  p[1] = false;
  for k in 2..=n {
    if p[k] {
      for i in 1.. {
        let ki = k.saturating_mul(i);
        if ki > n {
          break;
        }
        p[ki] = false;
        t[ki] *= -1;
        let kki = ki.saturating_mul(k);
        if kki > n {
          continue;
        }
        t[kki] = 0;
      }
    }
  }
  t.iter().sum()
}

fn main() {
  let ans = solve();
  println!("{}", ans);
}