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

class Program
{
    static int NN => int.Parse(ReadLine());
    static int[] NList => ReadLine().Split().Select(int.Parse).ToArray();
    static int[][] NArr(long n) => Enumerable.Repeat(0, (int)n).Select(_ => NList).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var n = NN;
        if (n == 0) WriteLine(0);
        else
        {
            var t = new System.Text.StringBuilder();
            t.Append("0.");
            for (var i = 0; i < n; ++i)
            {
                t.Append("142857"[i % 6]);
            }
            WriteLine(t.ToString());
        }
    }
}