using System;
using System.Collections.Generic;
using System.Linq;
using static System.Console;

class Program
{
    public static void Main()
    {
        var N = int.Parse(ReadLine());
        if (N == 0)
        {
            WriteLine(0);
            return;
        }
        Write("0.");
        for (int i = 0; i < N; i++) Write("142857"[i % 6]);
        WriteLine();
    }
}