import java.util.Scanner;

public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		long n = 0;
		n = sc.nextLong();

		long a = 100;
		int ans = 0;

		while (true) {
			ans++;
			long tmp = 0;
			tmp = (long) (a * 0.01);
			a += tmp;

			if(a >= n){
				System.out.println(ans);
				break;
			}

		}
	}
} import java.util.Scanner; Scanner java.util public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		long n = 0;
		n = sc.nextLong();

		long a = 100;
		int ans = 0;

		while (true) {
			ans++;
			long tmp = 0;
			tmp = (long) (a * 0.01);
			a += tmp;

			if(a >= n){
				System.out.println(ans);
				break;
			}

		}
	}
} Main public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		long n = 0;
		n = sc.nextLong();

		long a = 100;
		int ans = 0;

		while (true) {
			ans++;
			long tmp = 0;
			tmp = (long) (a * 0.01);
			a += tmp;

			if(a >= n){
				System.out.println(ans);
				break;
			}

		}
	} main {
		Scanner sc = new Scanner(System.in);
		long n = 0;
		n = sc.nextLong();

		long a = 100;
		int ans = 0;

		while (true) {
			ans++;
			long tmp = 0;
			tmp = (long) (a * 0.01);
			a += tmp;

			if(a >= n){
				System.out.println(ans);
				break;
			}

		}
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) long n = 0; n 0 n = sc.nextLong() n sc.nextLong() sc.nextLong sc long a = 100; a 100 int ans = 0; ans 0 while (true) {
			ans++;
			long tmp = 0;
			tmp = (long) (a * 0.01);
			a += tmp;

			if(a >= n){
				System.out.println(ans);
				break;
			}

		} true {
			ans++;
			long tmp = 0;
			tmp = (long) (a * 0.01);
			a += tmp;

			if(a >= n){
				System.out.println(ans);
				break;
			}

		} ans++ ans long tmp = 0; tmp 0 tmp = (long) (a * 0.01) tmp (long) (a * 0.01) a 0.01 a += tmp a tmp if(a >= n){
				System.out.println(ans);
				break;
			} a >= n a n {
				System.out.println(ans);
				break;
			} System.out.println(ans) System.out.println System.out System System.out ans break; String[] args args public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		long n = 0;
		n = sc.nextLong();

		long a = 100;
		int ans = 0;

		while (true) {
			ans++;
			long tmp = 0;
			tmp = (long) (a * 0.01);
			a += tmp;

			if(a >= n){
				System.out.println(ans);
				break;
			}

		}
	}
} public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		long n = 0;
		n = sc.nextLong();

		long a = 100;
		int ans = 0;

		while (true) {
			ans++;
			long tmp = 0;
			tmp = (long) (a * 0.01);
			a += tmp;

			if(a >= n){
				System.out.println(ans);
				break;
			}

		}
	}
} Main
import java.util.Scanner;

public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		long n = 0;
		n = sc.nextLong();

		long a = 100;
		int ans = 0;

		while (true) {
			ans++;
			long tmp = 0;
			tmp = (long) (a * 0.01);
			a += tmp;

			if(a >= n){
				System.out.println(ans);
				break;
			}

		}
	}
}