open Printf
open Scanf

let input_int () =
  scanf "%d\n" (fun k -> k)

let f () = 
  let n = input_int () in
  let rec loop tot a =
    if a=n then
      printf "%d\n" tot
    else
      loop (tot + ((n-1)/a)) (a+1)
  in
  loop 0 1

let () = f ()
