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

namespace yukicoder
{
    public class IO
    {
        public static string ReadStr() => Console.ReadLine();
        public static string[] ReadStrArr() => ReadStr().Split(' ');

        public static int ReadInt() => int.Parse(ReadStr());
        public static int[] ReadIntArr() => Array.ConvertAll(Console.ReadLine().Split(' '), int.Parse);

        public static double ReadDouble() => double.Parse(ReadStr());
        public static double[] ReadDoubleArr() => Array.ConvertAll(Console.ReadLine().Split(' '), double.Parse);

        public static long ReadLong() => long.Parse(ReadStr());
        public static long[] ReadLongArr() => Array.ConvertAll(Console.ReadLine().Split(' '), long.Parse);

        public static void Cout<T>(T value) => Console.WriteLine(value);
    }

    class Program
    {
        static void Main(string[] args)
        {
            int N = IO.ReadInt();
            IO.Cout(1 / (double)N);
        }
    }
}