import java.util.*;

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

class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		
		long x = sc.nextLong();
		long y = 100;
		int c = 0;
		
		while(true) {
			if(y >= x) {
				System.out.println(c);
				return;
			}
			y += y / 100;
			c++;
		}
		
	}
}