open System
open System.Text

let solve n =
  match n with
  | 0 -> "0"
  | _ -> 
    let loop = "142857"
    let loopLen = loop.Length
    let builder = StringBuilder("0.")

    let rec f (builder: StringBuilder) n =
      match n with
      | 0 -> builder
      | n -> f (builder.Append(loop)) (n-1)

    (f builder (n / loopLen)).Append(loop.Substring(0, (n % loopLen))).ToString()
  
let N = Console.ReadLine() |> int

solve N
|> Console.WriteLine