Scanf.scanf "%d" (fun n ->
    let k = (match n mod 10 with
    | 2 | 4 | 5 | 7 | 9 -> "hon"
    | 0 | 1 | 6 | 8 -> "pon"
    | 3 -> "bon"
    | _ -> failwith "??")
    in
    Printf.printf "%s\n" k
)