import java.io.BufferedReader;
import java.io.InputStreamReader;

public class No211 {
    public static void main(String[] args) {
        try {
            int[] prime = { 2, 3, 5, 7, 11, 13 };
            int[] composite = { 4, 6, 8, 9, 10, 12 };

            BufferedReader br = new BufferedReader(new InputStreamReader(
                    System.in));
            int N = Integer.parseInt(br.readLine());
            int count = 0;
            for (int i : composite) {
                for (int j : prime) {
                    if (i * j == N) {
                        count++;
                    }
                }
            }
            System.out.println(count / 36.0);
        } catch (Exception e) {
            System.err.println("Error:" + e.getMessage());
        }
    }
}