import java.util.Scanner;
public class Main {

	public static void main(String[] args) {
		Scanner stdIn = new Scanner(System.in);
		long x = stdIn.nextLong();
		long step = 0;
		long a = 100;
		while(a < x) {
			a+= a/100;
			step++;
		}
		System.out.println(step);
		
		
	}

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

	public static void main(String[] args) {
		Scanner stdIn = new Scanner(System.in);
		long x = stdIn.nextLong();
		long step = 0;
		long a = 100;
		while(a < x) {
			a+= a/100;
			step++;
		}
		System.out.println(step);
		
		
	}

} Main public static void main(String[] args) {
		Scanner stdIn = new Scanner(System.in);
		long x = stdIn.nextLong();
		long step = 0;
		long a = 100;
		while(a < x) {
			a+= a/100;
			step++;
		}
		System.out.println(step);
		
		
	} main {
		Scanner stdIn = new Scanner(System.in);
		long x = stdIn.nextLong();
		long step = 0;
		long a = 100;
		while(a < x) {
			a+= a/100;
			step++;
		}
		System.out.println(step);
		
		
	} Scanner stdIn = new Scanner(System.in); stdIn new Scanner(System.in) long x = stdIn.nextLong(); x stdIn.nextLong() stdIn.nextLong stdIn long step = 0; step 0 long a = 100; a 100 while(a < x) {
			a+= a/100;
			step++;
		} a < x a x {
			a+= a/100;
			step++;
		} a+= a/100 a a/100 a 100 step++ step System.out.println(step) System.out.println System.out System System.out step String[] args args public class Main {

	public static void main(String[] args) {
		Scanner stdIn = new Scanner(System.in);
		long x = stdIn.nextLong();
		long step = 0;
		long a = 100;
		while(a < x) {
			a+= a/100;
			step++;
		}
		System.out.println(step);
		
		
	}

} public class Main {

	public static void main(String[] args) {
		Scanner stdIn = new Scanner(System.in);
		long x = stdIn.nextLong();
		long step = 0;
		long a = 100;
		while(a < x) {
			a+= a/100;
			step++;
		}
		System.out.println(step);
		
		
	}

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

	public static void main(String[] args) {
		Scanner stdIn = new Scanner(System.in);
		long x = stdIn.nextLong();
		long step = 0;
		long a = 100;
		while(a < x) {
			a+= a/100;
			step++;
		}
		System.out.println(step);
		
		
	}

}
