Scanf.scanf "%d %d %d" (fun x y n ->
    let a = Array.init n (fun _ -> Scanf.scanf " %d" (fun a -> a)) in

    let rec loop i =
        if i = n - 1 then "YES" else (
            if a.(i) * y > a.(i + 1) * x then "NO" else loop (i + 1)
        )
    in
    loop 0 |> print_endline
)