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

public class Program
{
    public void Proc() {
        Reader.IsDebug = false;
        int n = int.Parse(Reader.ReadLine());
        int[] d = new int[DStr.Length+2];
        for(int i=0; i<DStr.Length; i++) {
            d[i+2] = int.Parse(DStr[i].ToString());
        }

        int[] ketaagari = new int[d.Length];
        int[] ansArr = new int[d.Length];

        for(int i=d.Length-1; i>=0; i--) {
            int tmp = d[i]*n + ketaagari[i];
            ansArr[i] = tmp % 10;
            if(i>=1) {
                ketaagari[i-1]+=(tmp%100)/10;
            }
            if(i>=2) {
                ketaagari[i-2]+=tmp/100;
            }
        }

        StringBuilder ans = new StringBuilder();
        for(int i=0; i<ansArr.Length; i++) {
            ans.Append(ansArr[i]);
            if(i==2) {
                ans.Append(".");
            }
        }
        string ansStr = ans.ToString().Trim(new char[]{'0'});
        if(ansStr.StartsWith(".")) {
            ansStr = "0" + ansStr;
        }
        Console.WriteLine(ansStr);
        
    }

    private string DStr = "01234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374757677787980818283848586878889909192939495969798991";


    public class Reader {
        public static bool IsDebug = true;
        private static System.IO.StringReader SReader;
        private static string InitText = @"


14


";
        public static string ReadLine() {
            if(IsDebug) {
                if(SReader == null) {
                    SReader = new System.IO.StringReader(InitText.Trim());
                }
                return SReader.ReadLine();
            } else {
                return Console.ReadLine();
            }
        }
    }
    public static void Main(string[] args)
    {
        Program prg = new Program();
        prg.Proc();
    }
}