open System [] let main argv = (fun _ -> Console.ReadLine()) |> Seq.initInfinite |> Seq.takeWhile ((<>) null) |> Seq.iter (fun (s : string) -> let arr = s.Split([|' '|]) let a = int64 arr.[0] let b = int64 arr.[1] /// solve test case and output answer printfn "%d" (abs (a - b)) ) 0