public class Program
{
    public static void Main()
    {
        int num = int.Parse(Console.ReadLine() ?? string.Empty);
        //string[] str = (Console.ReadLine() ?? string.Empty).Trim().Split(' ');
        //st0ring str = Console.ReadLine() ?? string.Empty;

        double d = 1 / num;
        Console.WriteLine(d);
    }
}