let main () =
  let n = read_int () in
  let count = ref 0 in
  (
    for a = 1 to n do
      for b = 1 to n / a do
        let c = n - a * b in
        if c > 0
        then count := !count + 1
      done
    done;
    Printf.printf "%d" !count;
    print_newline ()
  )

let _ = main ()
