let N = stdin.ReadLine() |> int
 
let cl n =
  match n%2 with
  | 0 -> n/2
  | _ -> 3*n+1 
 
let rec rfn i x xs =
  let c = cl x
  if List.contains c xs
    then i+1
    else rfn (i+1) (cl x) (c::xs)
 
rfn 1 N [N]
|> printfn "%d"