let pow x n m =
  let rec doit x n acc =
    if n = 0 then acc
    else doit (x * x mod m) (n / 2) (if n mod 2 = 0 then acc else acc * x mod m) in
  doit x n 1

let prime_p n =
  if n == 2 then true
  else if n < 2 || n mod 2 = 0 then false
  else if pow 2 (n - 1) n = 1 then true
  else false

let () =
  let p = [|2;3;5;7;11;13|] in
  let c = [|4;6;8;9;10;12|] in
  let k = read_int () in
  if prime_p k then print_endline "0.00000000000000000"
  else
    let rec doit cnt = function
      | (i, _) when i = 6 -> cnt
      | (i, j) when j = 6 -> doit cnt (i + 1, 0)
      | (i, j) -> doit (cnt + if p.(i)*c.(j) = k then 1 else 0) (i, j + 1) in
    let n = doit 0 (0, 0) in
    Printf.printf "%.12f\n" (float n /. 36.)