let [|h;w;a;b|] = stdin.ReadLine().Split() |> Array.map int

for i in 1..h do
 [for j in 1..w do yield (if (i <= b && j <= a) || (i > b && j > a) then "0" else "1")]
 |>List.reduce (fun x y -> x + y)
 |>stdout.WriteLine