let sosu_dice = [2; 3; 5; 7; 11; 13]
let comp_dice = [4; 6; 8; 9; 10; 12]

let count_ans n =
  let rec comp_loop sosu lst =
    match lst with
    | [] -> 0
    | x::xs ->
      if n = sosu * x then 1
      else comp_loop sosu xs
  in
  let rec sosu_loop lst result =
    match lst with
    | [] -> result
    | x::xs ->
      let nextResult =
        if n mod x = 0 then result + (comp_loop x comp_dice)
        else result
      in
      sosu_loop xs nextResult
  in
  sosu_loop sosu_dice 0

let () =
  let k = read_int () in
  let ans =
    if k < 8 || k > 156 then 0.
    else (float_of_int (count_ans k)) /. 36. in
  Printf.printf "%0.13f\n" ans