let () =
  let n, a, b = Scanf.scanf "%d %d %d\n" (fun n a b -> n, a, b) in
  let xs = Array.init n (fun _ -> Scanf.scanf "%d " (fun x -> x)) in
  Array.init (n - 1) (fun i -> min b (a * (xs.(i + 1) - xs.(i))))
  |> Array.fold_left ( + ) 0
  |> Printf.printf "%d\n"