let () =
    let split s =
        let rec loop i cur flag acc =
            if i = String.length s then ( if flag then cur :: acc else acc) else (
                match flag, s.[i] with
                | true,  ' ' -> loop (i + 1) "" false (cur :: acc)
                | false, ' ' -> loop (i + 1) "" false acc
                | true,  v   -> loop (i + 1) (Printf.sprintf "%s%c" cur v) true acc
                | false, v   -> loop (i + 1) (Printf.sprintf "%s%c" cur v) true acc
            )
        in
        List.map int_of_string (List.rev (loop 0 "" false []))
    in
    let main () =
        let n = int_of_string (read_line ()) in
        let p = Array.of_list (split (read_line ())) in
        let q = Array.copy p in
        let () = Array.sort compare q in
        let rec loop i acc =
            if i = n then acc else loop (i + 1) (if p.(i) <> q.(i) then acc + 1 else acc)
        in
        print_endline (if loop 0 0 <= 2 then "YES" else "NO")
    in
    main ()