let () =
    let main () =
        let n = int_of_string (read_line ()) in
        let s, t = Scanf.scanf "%s %s" (fun s t -> s, t) in
        let rec loop i acc =
            if i = n then acc else loop (i + 1)
            (Printf.sprintf "%s%c%c" acc s.[i] t.[i])
        in
        loop 0 "" |> print_endline
    in
    main ()