import java.util.Scanner;

public class Main {
	public static void main(String[] args){
		Scanner stdIn = new Scanner(System.in);
		long X = stdIn.nextLong();
		long ans = 0;
		long a = 100;
		for(;;){
			ans++;
			a = a + a/100;
			if(X <= a){
				break;
			}
		}
		System.out.println(ans);
		stdIn.close();
	}
} import java.util.Scanner; Scanner java.util public class Main {
	public static void main(String[] args){
		Scanner stdIn = new Scanner(System.in);
		long X = stdIn.nextLong();
		long ans = 0;
		long a = 100;
		for(;;){
			ans++;
			a = a + a/100;
			if(X <= a){
				break;
			}
		}
		System.out.println(ans);
		stdIn.close();
	}
} Main public static void main(String[] args){
		Scanner stdIn = new Scanner(System.in);
		long X = stdIn.nextLong();
		long ans = 0;
		long a = 100;
		for(;;){
			ans++;
			a = a + a/100;
			if(X <= a){
				break;
			}
		}
		System.out.println(ans);
		stdIn.close();
	} main {
		Scanner stdIn = new Scanner(System.in);
		long X = stdIn.nextLong();
		long ans = 0;
		long a = 100;
		for(;;){
			ans++;
			a = a + a/100;
			if(X <= a){
				break;
			}
		}
		System.out.println(ans);
		stdIn.close();
	} Scanner stdIn = new Scanner(System.in); stdIn new Scanner(System.in) long X = stdIn.nextLong(); X stdIn.nextLong() stdIn.nextLong stdIn long ans = 0; ans 0 long a = 100; a 100 for(;;){
			ans++;
			a = a + a/100;
			if(X <= a){
				break;
			}
		} ; {
			ans++;
			a = a + a/100;
			if(X <= a){
				break;
			}
		} {
			ans++;
			a = a + a/100;
			if(X <= a){
				break;
			}
		} ans++ ans a = a + a/100 a a + a/100 a a/100 a 100 if(X <= a){
				break;
			} X <= a X a {
				break;
			} break; System.out.println(ans) System.out.println System.out System System.out ans stdIn.close() stdIn.close stdIn String[] args args public class Main {
	public static void main(String[] args){
		Scanner stdIn = new Scanner(System.in);
		long X = stdIn.nextLong();
		long ans = 0;
		long a = 100;
		for(;;){
			ans++;
			a = a + a/100;
			if(X <= a){
				break;
			}
		}
		System.out.println(ans);
		stdIn.close();
	}
} public class Main {
	public static void main(String[] args){
		Scanner stdIn = new Scanner(System.in);
		long X = stdIn.nextLong();
		long ans = 0;
		long a = 100;
		for(;;){
			ans++;
			a = a + a/100;
			if(X <= a){
				break;
			}
		}
		System.out.println(ans);
		stdIn.close();
	}
} Main
import java.util.Scanner;

public class Main {
	public static void main(String[] args){
		Scanner stdIn = new Scanner(System.in);
		long X = stdIn.nextLong();
		long ans = 0;
		long a = 100;
		for(;;){
			ans++;
			a = a + a/100;
			if(X <= a){
				break;
			}
		}
		System.out.println(ans);
		stdIn.close();
	}
}