import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;

public class No211 {

    public static void main(String[] args) {
        Scanner s = new Scanner(System.in);
        int num = s.nextInt();
        int[] primes = {2, 3, 5, 7, 11, 13};
        int[] composites = {4, 6, 8, 9, 10, 12};
        Map<Integer, Double> map = new HashMap<>();
        for (int prime : primes) {
            for (int composite : composites) {
                int tmp = prime * composite;
                if (map.containsKey(tmp)) {
                    map.put(tmp, map.get(tmp) + 1);
                } else {
                    map.put(tmp, 1d);
                }
            }
        }
        double prop = 0L;
        if (map.containsKey(num)) {
            prop = map.get(num) / 36;
        }
        System.out.println(prop);
    }
}