let n = Scanf.sscanf (read_line ()) "%d" @@ fun n -> n

let code_a = int_of_char 'a'
let char_of_code code = char_of_int (code_a + code)

let rec loop res = function
  | 0 -> res |> List.map Char.escaped |> String.concat "" |> print_endline
  | n -> let n = n - 1 in loop ((char_of_code (n mod 26)) :: res) (n / 26)

let () = loop [] n
