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 s=100;
		int k=0;
		while(s<X) {
			s+=s/100;
			k++;
		}
		System.out.println(k);
	}

} 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 s=100;
		int k=0;
		while(s<X) {
			s+=s/100;
			k++;
		}
		System.out.println(k);
	}

} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		long X = sc.nextLong();
		sc.close();
		long s=100;
		int k=0;
		while(s<X) {
			s+=s/100;
			k++;
		}
		System.out.println(k);
	} main {
		Scanner sc = new Scanner(System.in);
		long X = sc.nextLong();
		sc.close();
		long s=100;
		int k=0;
		while(s<X) {
			s+=s/100;
			k++;
		}
		System.out.println(k);
	} 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 s=100; s 100 int k=0; k 0 while(s<X) {
			s+=s/100;
			k++;
		} s<X s X {
			s+=s/100;
			k++;
		} s+=s/100 s s/100 s 100 k++ k System.out.println(k) System.out.println System.out System System.out k 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 s=100;
		int k=0;
		while(s<X) {
			s+=s/100;
			k++;
		}
		System.out.println(k);
	}

} public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		long X = sc.nextLong();
		sc.close();
		long s=100;
		int k=0;
		while(s<X) {
			s+=s/100;
			k++;
		}
		System.out.println(k);
	}

} 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 s=100;
		int k=0;
		while(s<X) {
			s+=s/100;
			k++;
		}
		System.out.println(k);
	}

}