let solve a b =
  if a = b then sqrt (a *. a +. b *. b)
  else (
    let x, y = (min a b), (max a b) in
    sqrt (y *. y -. x *. x))

let () =
  let a, b = read_line () |>
             Str.split (Str.regexp_string " ") |>
             List.map float_of_string |>
             fun lst -> (List.nth lst 0, List.nth lst 1)
  in
  solve a b |> (Printf.printf "%0.7f\n")