import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		long x = sc.nextLong();
		sc.close();
		long f = 100L;
		long ans = 0L;
		while (f < x) {
			long p = (long)(f * 0.01);
			f += p;
			ans++;
		}
		System.out.println(ans);
	}
} import java.util.Scanner; Scanner java.util public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		long x = sc.nextLong();
		sc.close();
		long f = 100L;
		long ans = 0L;
		while (f < x) {
			long p = (long)(f * 0.01);
			f += p;
			ans++;
		}
		System.out.println(ans);
	}
} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		long x = sc.nextLong();
		sc.close();
		long f = 100L;
		long ans = 0L;
		while (f < x) {
			long p = (long)(f * 0.01);
			f += p;
			ans++;
		}
		System.out.println(ans);
	} main {
		Scanner sc = new Scanner(System.in);
		long x = sc.nextLong();
		sc.close();
		long f = 100L;
		long ans = 0L;
		while (f < x) {
			long p = (long)(f * 0.01);
			f += p;
			ans++;
		}
		System.out.println(ans);
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) long x = sc.nextLong(); x sc.nextLong() sc.nextLong sc sc.close() sc.close sc long f = 100L; f 100L long ans = 0L; ans 0L while (f < x) {
			long p = (long)(f * 0.01);
			f += p;
			ans++;
		} f < x f x {
			long p = (long)(f * 0.01);
			f += p;
			ans++;
		} long p = (long)(f * 0.01); p (long)(f * 0.01) f 0.01 f += p f p ans++ ans System.out.println(ans) System.out.println System.out System System.out ans String[] args args public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		long x = sc.nextLong();
		sc.close();
		long f = 100L;
		long ans = 0L;
		while (f < x) {
			long p = (long)(f * 0.01);
			f += p;
			ans++;
		}
		System.out.println(ans);
	}
} public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		long x = sc.nextLong();
		sc.close();
		long f = 100L;
		long ans = 0L;
		while (f < x) {
			long p = (long)(f * 0.01);
			f += p;
			ans++;
		}
		System.out.println(ans);
	}
} Main
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		long x = sc.nextLong();
		sc.close();
		long f = 100L;
		long ans = 0L;
		while (f < x) {
			long p = (long)(f * 0.01);
			f += p;
			ans++;
		}
		System.out.println(ans);
	}
}