open System let ri () = stdin.ReadLine() |> int let ria () = stdin.ReadLine().Split() |> Array.map int type Sol() = member this.Solve() = let [|a;b|] = stdin.ReadLine().Split() |> Array.map double |> Array.sort b*b - a*a |> sqrt |> printfn "%.8f" () let mySol = new Sol() mySol.Solve()