let () =
  let n = Scanf.scanf "%d " (fun a -> a) in
  let c_lst = Array.to_list @@ Array.init n (fun _ -> Scanf.scanf "%c " (fun a -> a)) in
  let res = List.sort_uniq compare c_lst |> List.length in
  Printf.printf "%s\n" @@ if res = 4 then "Four" else "Three"

