Scanf.scanf "%d" (fun n ->
    let sum d =
        let rec loop i acc =
            if i = 0 then acc else loop (i / 10) (acc + i mod 10)
        in
        loop d 0
    in
    let rec loop i d =
        if i = 0 then d else loop (i - 1) (sum d)
    in
    loop 100 n |> Printf.printf "%d\n"
)