import java.util.*;

class Main {
    private static Scanner sc;

    public static void main(final String[] args) {
        sc = new Scanner(System.in);
        long a = sc.nextLong(),ans = 0,num = 100;
        while(true){
            if(num >= a){
                System.out.println(ans);
                break;
            }  
            num += num/100;
            ans++;
        }
    }
}





 import java.util.*; util.* java class Main {
    private static Scanner sc;

    public static void main(final String[] args) {
        sc = new Scanner(System.in);
        long a = sc.nextLong(),ans = 0,num = 100;
        while(true){
            if(num >= a){
                System.out.println(ans);
                break;
            }  
            num += num/100;
            ans++;
        }
    }
} Main private static Scanner sc; sc public static void main(final String[] args) {
        sc = new Scanner(System.in);
        long a = sc.nextLong(),ans = 0,num = 100;
        while(true){
            if(num >= a){
                System.out.println(ans);
                break;
            }  
            num += num/100;
            ans++;
        }
    } main {
        sc = new Scanner(System.in);
        long a = sc.nextLong(),ans = 0,num = 100;
        while(true){
            if(num >= a){
                System.out.println(ans);
                break;
            }  
            num += num/100;
            ans++;
        }
    } sc = new Scanner(System.in) sc new Scanner(System.in) long a = sc.nextLong() a sc.nextLong() sc.nextLong sc ans = 0 ans 0 num = 100; num 100 while(true){
            if(num >= a){
                System.out.println(ans);
                break;
            }  
            num += num/100;
            ans++;
        } true {
            if(num >= a){
                System.out.println(ans);
                break;
            }  
            num += num/100;
            ans++;
        } if(num >= a){
                System.out.println(ans);
                break;
            } num >= a num a {
                System.out.println(ans);
                break;
            } System.out.println(ans) System.out.println System.out System System.out ans break; num += num/100 num num/100 num 100 ans++ ans final String[] args args
import java.util.*;

class Main {
    private static Scanner sc;

    public static void main(final String[] args) {
        sc = new Scanner(System.in);
        long a = sc.nextLong(),ans = 0,num = 100;
        while(true){
            if(num >= a){
                System.out.println(ans);
                break;
            }  
            num += num/100;
            ans++;
        }
    }
}






