import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class Main{

	public static void main(String[] args) {

		Scanner scanner = new Scanner(System.in);
		long n = Long.parseLong(scanner.nextLine());
		long a = 100;
		long x = 0;
		while(a < n) {

			a += a / 100;
			x++;
		}
		System.out.println(x);



	}

} import java.util.ArrayList; ArrayList java.util import java.util.List; List java.util import java.util.Scanner; Scanner java.util public class Main{

	public static void main(String[] args) {

		Scanner scanner = new Scanner(System.in);
		long n = Long.parseLong(scanner.nextLine());
		long a = 100;
		long x = 0;
		while(a < n) {

			a += a / 100;
			x++;
		}
		System.out.println(x);



	}

} Main public static void main(String[] args) {

		Scanner scanner = new Scanner(System.in);
		long n = Long.parseLong(scanner.nextLine());
		long a = 100;
		long x = 0;
		while(a < n) {

			a += a / 100;
			x++;
		}
		System.out.println(x);



	} main {

		Scanner scanner = new Scanner(System.in);
		long n = Long.parseLong(scanner.nextLine());
		long a = 100;
		long x = 0;
		while(a < n) {

			a += a / 100;
			x++;
		}
		System.out.println(x);



	} Scanner scanner = new Scanner(System.in); scanner new Scanner(System.in) long n = Long.parseLong(scanner.nextLine()); n Long.parseLong(scanner.nextLine()) Long.parseLong Long scanner.nextLine() scanner.nextLine scanner long a = 100; a 100 long x = 0; x 0 while(a < n) {

			a += a / 100;
			x++;
		} a < n a n {

			a += a / 100;
			x++;
		} a += a / 100 a a / 100 a 100 x++ x System.out.println(x) System.out.println System.out System System.out x String[] args args public class Main{

	public static void main(String[] args) {

		Scanner scanner = new Scanner(System.in);
		long n = Long.parseLong(scanner.nextLine());
		long a = 100;
		long x = 0;
		while(a < n) {

			a += a / 100;
			x++;
		}
		System.out.println(x);



	}

} public class Main{

	public static void main(String[] args) {

		Scanner scanner = new Scanner(System.in);
		long n = Long.parseLong(scanner.nextLine());
		long a = 100;
		long x = 0;
		while(a < n) {

			a += a / 100;
			x++;
		}
		System.out.println(x);



	}

} Main
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class Main{

	public static void main(String[] args) {

		Scanner scanner = new Scanner(System.in);
		long n = Long.parseLong(scanner.nextLine());
		long a = 100;
		long x = 0;
		while(a < n) {

			a += a / 100;
			x++;
		}
		System.out.println(x);



	}

}
