import java.util.*;

public class Yukicoder211{
	public static void main(String[] args){
		Scanner scan = new Scanner(System.in);
		int k = scan.nextInt();
		int count = 0;
		int[] sosuu = {2,3,5,7,11,13};
		int[] gousei = {4,6,8,9,10,12};
		int[][] kai = new int[6][6];
		for(int i = 0;i < 6;i++){
			for(int j = 0;j < 6;j++){
				if(k == sosuu[i] * gousei[j])	count++;
			}
		}
		System.out.println(count / 36.0);
	}
}