using System;

public class Program

{

    public static void Main()

    {

        double declineProduction = double.Parse(Console.ReadLine());

        int yearCounter = 2010;

        while (declineProduction >= 10)

        {

            declineProduction = 0.9 * declineProduction;

            yearCounter += 1;

        }

        Console.WriteLine(yearCounter);

    }

}