let () =
  let x, y, n = Scanf.scanf "%d %d %d " (fun x y n -> x, y, n) in
  let x, y = float x /. 3600. *. 1000., float y /. 3600. *. 1000. in
  let a = Array.init n (fun _ -> Scanf.scanf "%d " (fun i -> float i)) in
  let rec doit i =
    if i = n then true
    else
      if y *. a.(i-1) /. x > a.(i) then false
      else doit (i + 1) in
  print_endline (if doit 1 then "YES" else "NO")