import java.util.*;
import java.math.*;


class Main
{
	public static void main (String[] args)
	{
		double S;
		Scanner input = new Scanner(System.in);
        S = input.nextDouble();
        S = Math.ceil((Math.log(S/100+1)/Math.log(1.1)));
        int a = (int) S;
		System.out.print(a);
	}
}