import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Scanner;



public class Main {

	public static class pair implements Comparable<pair> {
		int id;
		int ans;
 
		pair(int x, int y) {
 
			id = x;
			ans = y;
 
		}
 
		public pair() {
 
		}
 
		public int compareTo(pair o) {
			// TODO Auto-generated method stub
 
			return this.id - o.id;
		}
	}
 
//	static int mod = (int) 998244353.;
	static ArrayList<Integer> gr[];
	static int[] ar;
	static Scanner sc = new Scanner(System.in);
	static int pri[] = new int[(int) 1e6 + 5];
	static StringBuilder out = new StringBuilder();
 
	//static long dp[];
 
	public static void main(String[] args) throws IOException {
		int t =1;//sc.nextInt();
		
		while (t-- > 0) {
 
			long ru=sc.nextLong();
			long val=100;
			long n=0;
			while(val<ru) {
				val+=val/100;
				n++;
			}
			System.out.println(n);
			
			
		}
		
		System.out.println(out);
	}
	
 
	
} import java.io.IOException; IOException java.io import java.util.ArrayList; ArrayList java.util import java.util.Arrays; Arrays java.util import java.util.Scanner; Scanner java.util public class Main {

	public static class pair implements Comparable<pair> {
		int id;
		int ans;
 
		pair(int x, int y) {
 
			id = x;
			ans = y;
 
		}
 
		public pair() {
 
		}
 
		public int compareTo(pair o) {
			// TODO Auto-generated method stub
 
			return this.id - o.id;
		}
	}
 
//	static int mod = (int) 998244353.;
	static ArrayList<Integer> gr[];
	static int[] ar;
	static Scanner sc = new Scanner(System.in);
	static int pri[] = new int[(int) 1e6 + 5];
	static StringBuilder out = new StringBuilder();
 
	//static long dp[];
 
	public static void main(String[] args) throws IOException {
		int t =1;//sc.nextInt();
		
		while (t-- > 0) {
 
			long ru=sc.nextLong();
			long val=100;
			long n=0;
			while(val<ru) {
				val+=val/100;
				n++;
			}
			System.out.println(n);
			
			
		}
		
		System.out.println(out);
	}
	
 
	
} Main //	static int mod = (int) 998244353.;
	static ArrayList<Integer> gr[]; gr static int[] ar; ar static Scanner sc = new Scanner(System.in); sc new Scanner(System.in) static int pri[] = new int[(int) 1e6 + 5]; pri new int[(int) 1e6 + 5] (int) 1e6 + 5 (int) 1e6 5 static StringBuilder out = new StringBuilder(); out new StringBuilder() public static void main(String[] args) throws IOException {
		int t =1;//sc.nextInt();
		
		while (t-- > 0) {
 
			long ru=sc.nextLong();
			long val=100;
			long n=0;
			while(val<ru) {
				val+=val/100;
				n++;
			}
			System.out.println(n);
			
			
		}
		
		System.out.println(out);
	} main {
		int t =1;//sc.nextInt();
		
		while (t-- > 0) {
 
			long ru=sc.nextLong();
			long val=100;
			long n=0;
			while(val<ru) {
				val+=val/100;
				n++;
			}
			System.out.println(n);
			
			
		}
		
		System.out.println(out);
	} int t =1; t 1 while (t-- > 0) {
 
			long ru=sc.nextLong();
			long val=100;
			long n=0;
			while(val<ru) {
				val+=val/100;
				n++;
			}
			System.out.println(n);
			
			
		} t-- > 0 t-- t 0 {
 
			long ru=sc.nextLong();
			long val=100;
			long n=0;
			while(val<ru) {
				val+=val/100;
				n++;
			}
			System.out.println(n);
			
			
		} long ru=sc.nextLong(); ru sc.nextLong() sc.nextLong sc long val=100; val 100 long n=0; n 0 while(val<ru) {
				val+=val/100;
				n++;
			} val<ru val ru {
				val+=val/100;
				n++;
			} val+=val/100 val val/100 val 100 n++ n System.out.println(n) System.out.println System.out System System.out n System.out.println(out) System.out.println System.out System System.out out String[] args args public static class pair implements Comparable<pair> {
		int id;
		int ans;
 
		pair(int x, int y) {
 
			id = x;
			ans = y;
 
		}
 
		public pair() {
 
		}
 
		public int compareTo(pair o) {
			// TODO Auto-generated method stub
 
			return this.id - o.id;
		}
	} pair int id; id int ans; ans pair(int x, int y) {
 
			id = x;
			ans = y;
 
		} pair {
 
			id = x;
			ans = y;
 
		} id = x id x ans = y ans y int x x int y y public pair() {
 
		} pair {
 
		} public int compareTo(pair o) {
			// TODO Auto-generated method stub
 
			return this.id - o.id;
		} compareTo {
			// TODO Auto-generated method stub
 
			return this.id - o.id;
		} return this.id - o.id; this.id - o.id this.id this this.id o.id o o.id pair o o Comparable public class Main {

	public static class pair implements Comparable<pair> {
		int id;
		int ans;
 
		pair(int x, int y) {
 
			id = x;
			ans = y;
 
		}
 
		public pair() {
 
		}
 
		public int compareTo(pair o) {
			// TODO Auto-generated method stub
 
			return this.id - o.id;
		}
	}
 
//	static int mod = (int) 998244353.;
	static ArrayList<Integer> gr[];
	static int[] ar;
	static Scanner sc = new Scanner(System.in);
	static int pri[] = new int[(int) 1e6 + 5];
	static StringBuilder out = new StringBuilder();
 
	//static long dp[];
 
	public static void main(String[] args) throws IOException {
		int t =1;//sc.nextInt();
		
		while (t-- > 0) {
 
			long ru=sc.nextLong();
			long val=100;
			long n=0;
			while(val<ru) {
				val+=val/100;
				n++;
			}
			System.out.println(n);
			
			
		}
		
		System.out.println(out);
	}
	
 
	
} public class Main {

	public static class pair implements Comparable<pair> {
		int id;
		int ans;
 
		pair(int x, int y) {
 
			id = x;
			ans = y;
 
		}
 
		public pair() {
 
		}
 
		public int compareTo(pair o) {
			// TODO Auto-generated method stub
 
			return this.id - o.id;
		}
	}
 
//	static int mod = (int) 998244353.;
	static ArrayList<Integer> gr[];
	static int[] ar;
	static Scanner sc = new Scanner(System.in);
	static int pri[] = new int[(int) 1e6 + 5];
	static StringBuilder out = new StringBuilder();
 
	//static long dp[];
 
	public static void main(String[] args) throws IOException {
		int t =1;//sc.nextInt();
		
		while (t-- > 0) {
 
			long ru=sc.nextLong();
			long val=100;
			long n=0;
			while(val<ru) {
				val+=val/100;
				n++;
			}
			System.out.println(n);
			
			
		}
		
		System.out.println(out);
	}
	
 
	
} Main
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Scanner;



public class Main {

	public static class pair implements Comparable<pair> {
		int id;
		int ans;
 
		pair(int x, int y) {
 
			id = x;
			ans = y;
 
		}
 
		public pair() {
 
		}
 
		public int compareTo(pair o) {
			// TODO Auto-generated method stub
 
			return this.id - o.id;
		}
	}
 
//	static int mod = (int) 998244353.;
	static ArrayList<Integer> gr[];
	static int[] ar;
	static Scanner sc = new Scanner(System.in);
	static int pri[] = new int[(int) 1e6 + 5];
	static StringBuilder out = new StringBuilder();
 
	//static long dp[];
 
	public static void main(String[] args) throws IOException {
		int t =1;//sc.nextInt();
		
		while (t-- > 0) {
 
			long ru=sc.nextLong();
			long val=100;
			long n=0;
			while(val<ru) {
				val+=val/100;
				n++;
			}
			System.out.println(n);
			
			
		}
		
		System.out.println(out);
	}
	
 
	
}