using System;
using System.Collections.Generic;
using System.Collections;
using System.Linq;


namespace tes
{
	class contest
	{
		static void Main(string[] args)
		{
			 
           var num = int.Parse(Console.ReadLine());

            string D = "0.1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374757677787980818283848586878889909192939495969798991";

            var arr = new string[19];

            for (int i = 0; i < 19; i++)
            {
                arr[i] = D.Substring(2 + (i * 10), 10);
            }



            var change = new long[19];
            for (int i = 0; i < 19; i++)
            {
                string t = arr[i];
                long tmp = 0;
                if (t[0] == '0')
                {
                    tmp = long.Parse(t.Substring(1));
                }
                else
                {
                    tmp = long.Parse(t);
                }

                change[i] = tmp * num;
            }

            string ans = "";

            var over = new long[19];
            for (int i = 0; i < 19; i++)
            {
                long tmp = change[i];

                if (i % 2 == 1)
                {
                    int len = tmp.ToString().Length;
                    if (tmp.ToString().Length > 10)
                    {

                        over[i] = long.Parse(tmp.ToString().Substring(0, len - 10));
                        arr[i] = tmp.ToString().Substring(len - 10);
                    }
                    else if (len < 10)
                    {
                        over[i] = -1;
                        arr[i] = tmp.ToString();
                    }
                    else
                    {
                        arr[i] = tmp.ToString();
                    }

                }
                else
                {
                    int len = tmp.ToString().Length;
                    if (tmp.ToString().Length > 10)
                    {

                        over[i] = long.Parse(tmp.ToString().Substring(0, len - 10));
                        arr[i] = tmp.ToString().Substring(len - 10);
                    }
                    else
                    {
                        arr[i] = tmp.ToString();
                    }

                }

            }

            for (int i = 0; i < 19; i++)
            {
                if (i == 0)
                {
                    long f = long.Parse(arr[i]);
                    if(over[i+1]>0)
                    {
                        f += over[i + 1];
                    }
                    arr[i] = f.ToString();

                    if (over[0] > 0) ans += over[0].ToString() + "." + arr[i].ToString();
                    else ans += "0." + arr[i].ToString();

                    if (over[i + 1] < 0) ans += "0";
                }
                else if (i < 18 && (over[i + 1] > 0))
                {
                    string l = arr[i].Substring(0,6);
                    //l += "000";
                    string r = arr[i].Substring(6);
                    long tmp = long.Parse(r) + over[i + 1];


                    ans += l+tmp.ToString();
                }
                else if (i < 18 && over[i + 1] < 0)
                {
                    ans += arr[i].ToString() + "0";
                }
                else
                {
                    ans += arr[i].ToString();
                }


            }

            Console.WriteLine(ans);
		}				 
	}
}