using System;
using static System.Console;
using static System.Math;
using System.Linq;

public class Hello{
    public static void Main(){
        int a = int.Parse(ReadLine());
        if(a==0){
            WriteLine(0);
        }else{
            Write("0.");
            string b = "142857";
            for(int i=0;i<a;i++){
                int c = i%6;
                Write(b[c]);
            }
            WriteLine();
        }
    }
}