let () =
  Scanf.scanf "%d %d %d" @@ fun n a b ->
  let p = Array.init n (fun _ -> Scanf.scanf " %d" (fun x -> x)) in
  Array.fold_left (fun (d, y) x -> (d + min b (a * (x-y)), x)) (0, p.(0)) p
  |> fst |> Printf.printf "%d\n"