(* --------------Encoder-------------- *)
(* -----function----- *)
(*
let encoder = 0
*)

(* -------test------- *)
(* ----------------------------------- *)

(* --------------Decoder-------------- *)
(* -----function----- *)
(*
let decoder ans = ""
*)

(* -------test------- *)
(* ----------------------------------- *)

(* --------------Processor-------------- *)
(* -----function----- *)
(*
let processor dat = 0
*)

(* -------test------- *)
(* ----------------------------------- *)


(* ----------------main---------------- *)
(*
let () = print_endline (decoder (processor encoder))
*)
(* ------------------------------------ *)
let mod1 x y = 
        if x mod y > 0 then
                1
        else
                0

let () = Scanf.scanf "%d %d %d %d" (fun tlife tattack alife aattack -> 
        let tturn = (tlife / aattack) + mod1 tlife aattack in
        let aturn = (alife / tattack) + mod1 alife tattack in
        if tturn >= aturn then
                "Yes"
        else
                "No"
) |> print_endline

