Scanf.scanf "%d" (fun k ->
    let dump a =
        if a > 10 then Printf.printf "%c%c\n" "@ABCDE".[a mod 10] "@ABCDE".[a / 10] else
                       Printf.printf "%c\n" "@ABCDE".[a]
    in
    let rec loop i q0 q1 q2 q3 =
        if i = k then (dump q0; dump q1; dump q2; dump q3) else
            match i mod 4 with
            | 0 -> loop (i + 1) (q0 / 10) (q1 + (q0 mod 10) * 10) q2 q3
            | 1 -> loop (i + 1) q0 (q1 / 10) (q2 + (q1 mod 10) * 10) q3
            | 2 -> loop (i + 1) q0 q1 (q2 / 10) (q3 + (q2 mod 10) * 10)
            | _ -> loop (i + 1) (q0 + (q3 mod 10) * 10) q1 q2 (q3 / 10)
    in
    loop 0 51 2 3 4
)