package main

import "fmt"

func main() {
	var K int
	fmt.Scan(&K)
	d1 := []int{2, 3, 5, 7, 11, 13}
	d2 := []int{4, 6, 8, 9, 10, 12}
	m := make(map[int]int, 36)
	for _, v := range d1 {
		for _, w := range d2 {
			m[v*w]++
		}
	}
	fmt.Println(float64(m[K]) * (1.0 / 36))
}