package main

import (
  "fmt"
)

func main() {
  prime_number_dice := [6]int{2, 3, 5, 7, 11, 13}
  composite_number_dice := [6]int{4, 6, 8, 9, 10, 12}
  counter := map[int]int{}

  for _, x := range prime_number_dice {
    for _, y := range composite_number_dice {
      counter[x * y]++
    }
  }

  var K int
  fmt.Scanf("%d", &K)
  fmt.Println(float64(counter[K]) / 36)
}