using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace yukicoder_211 {
    class Program {
        static void Main(string[] args) {
            int n = int.Parse(Console.ReadLine());
            int[] a = { 2, 3, 5, 7, 11, 13 };
            int[] b = { 4, 6, 8, 9, 10, 12 };
            double count = 0;
            for(int i = 0; i < 6; i++) {
                for(int k = 0; k < 6; k++) {
                    if (a[i] * b[k] == n) count++;
                }
            }
            Console.WriteLine(count / 36);
            Console.ReadLine();
        }
    }
}