type ABC(stream:System.IO.TextReader) =
  member this.Scan1 f = stream.ReadLine() |> f
  member this.Scan2 f = stream.ReadLine().Split() |> Array.map f |> (fun a -> (a.[0], a.[1]))
  member this.Scan3 f = stream.ReadLine().Split() |> Array.map f |> (fun a -> (a.[0], a.[1], a.[2]))
  member this.Scan4 f = stream.ReadLine().Split() |> Array.map f |> (fun a -> (a.[0], a.[1], a.[2], a.[3]))
  member this.ScanVecH f = stream.ReadLine().Split() |> Array.map f
  member this.ScanVecV n f = [| for i in 1..n -> stream.ReadLine() |> f |]
  member this.ScanMatrix n f  = [| for i in 1..n -> stream.ReadLine().Split() |> Array.map f |]
  member this.ScanCharMatrix n = [| for i in 1..n -> stream.ReadLine().ToCharArray() |]
  member this.Close () = stream.Close()

let util = ABC(stdin)

let L, R = util.Scan2 int

if (R-L >= 2020) // for safety. not sure the boundary 
then
  printfn "0"
else
  [ for i in L..R do
    for j in i+1..R do
      yield ((i % 2019) * (j % 2019)) % 2019
  ]
  |> List.min
  |> printfn "%d"

util.Close()
