import java.util.*;

public class Main {
	static Scanner sc = new Scanner(System.in);
	public static void main(String[] args) {
		int n = sc.nextInt();
		int num = 0;
		
		int[] a = {2,3,5,7,11,13};
		int[] b = {4,6,8,9,10,12};
		for (int i=0; i<6; i++) {
			for (int j=0; j<6; j++) {
				if (a[i]*b[j]==n) {num++;}
			}
		}
		
		double x = num;
		double y = 36;
		System.out.println(x/y);
	}
}