// F#
[]
let main argv =
let rec count n =
match n with
| 0 -> 1.0
| n -> 1.0 / (2.0 * (float n) + 1.0) + count (n-1)
let n = System.Console.ReadLine() |> System.Int32.Parse
let s = count n
printf "Result: %f" s
System.Console.ReadKey true |> ignore
0