import java.util.*;

public class Main {

	public static void main(String[] args) {
	
		Scanner sc = new Scanner(System.in);
		long x = sc.nextLong();
		long m = 100L;
		long y = 0L;
		while (m < x) {
			y++;
			m = m + m / 100;
		}
		System.out.println(y);
	}
} import java.util.*; util.* java public class Main {

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

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

	public static void main(String[] args) {
	
		Scanner sc = new Scanner(System.in);
		long x = sc.nextLong();
		long m = 100L;
		long y = 0L;
		while (m < x) {
			y++;
			m = m + m / 100;
		}
		System.out.println(y);
	}
} Main
import java.util.*;

public class Main {

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