import java.io.*;
import java.util.*;

public class Main {

	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		long target = sc.nextLong();
		long base=100;
		int counts=0;
		while(base<target) {
			base+= (base/100);
			counts++;
		}
		System.out.println(counts);
	}

	static class Pair {
		int x;
		int y;

		public Pair(int x, int y) {
			this.x = x;
			this.y = y;
		}

	}

	static class Scanner {
		StringTokenizer st;
		BufferedReader br;

		public Scanner(InputStream s) {
			br = new BufferedReader(new InputStreamReader(s));
		}

		public Scanner(String file) throws FileNotFoundException {
			br = new BufferedReader(new FileReader(file));
		}

		public String next() throws IOException {
			while (st == null || !st.hasMoreTokens())
				st = new StringTokenizer(br.readLine());
			return st.nextToken();
		}

		public int nextInt() throws IOException {
			return Integer.parseInt(next());
		}

		public long nextLong() throws IOException {
			return Long.parseLong(next());
		}

		public String nextLine() throws IOException {
			return br.readLine();
		}

		public double nextDouble() throws IOException {
			return Double.parseDouble(next());
		}

		public boolean ready() throws IOException {
			return br.ready();
		}

	}
} import java.io.*; io.* java import java.util.*; util.* java public class Main {

	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		long target = sc.nextLong();
		long base=100;
		int counts=0;
		while(base<target) {
			base+= (base/100);
			counts++;
		}
		System.out.println(counts);
	}

	static class Pair {
		int x;
		int y;

		public Pair(int x, int y) {
			this.x = x;
			this.y = y;
		}

	}

	static class Scanner {
		StringTokenizer st;
		BufferedReader br;

		public Scanner(InputStream s) {
			br = new BufferedReader(new InputStreamReader(s));
		}

		public Scanner(String file) throws FileNotFoundException {
			br = new BufferedReader(new FileReader(file));
		}

		public String next() throws IOException {
			while (st == null || !st.hasMoreTokens())
				st = new StringTokenizer(br.readLine());
			return st.nextToken();
		}

		public int nextInt() throws IOException {
			return Integer.parseInt(next());
		}

		public long nextLong() throws IOException {
			return Long.parseLong(next());
		}

		public String nextLine() throws IOException {
			return br.readLine();
		}

		public double nextDouble() throws IOException {
			return Double.parseDouble(next());
		}

		public boolean ready() throws IOException {
			return br.ready();
		}

	}
} Main public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		long target = sc.nextLong();
		long base=100;
		int counts=0;
		while(base<target) {
			base+= (base/100);
			counts++;
		}
		System.out.println(counts);
	} main {
		Scanner sc = new Scanner(System.in);
		long target = sc.nextLong();
		long base=100;
		int counts=0;
		while(base<target) {
			base+= (base/100);
			counts++;
		}
		System.out.println(counts);
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) long target = sc.nextLong(); target sc.nextLong() sc.nextLong sc long base=100; base 100 int counts=0; counts 0 while(base<target) {
			base+= (base/100);
			counts++;
		} base<target base target {
			base+= (base/100);
			counts++;
		} base+= (base/100) base (base/100) base 100 counts++ counts System.out.println(counts) System.out.println System.out System System.out counts String[] args args static class Pair {
		int x;
		int y;

		public Pair(int x, int y) {
			this.x = x;
			this.y = y;
		}

	} Pair int x; x int y; y public Pair(int x, int y) {
			this.x = x;
			this.y = y;
		} Pair {
			this.x = x;
			this.y = y;
		} this.x = x this.x this this.x x this.y = y this.y this this.y y int x x int y y static class Scanner {
		StringTokenizer st;
		BufferedReader br;

		public Scanner(InputStream s) {
			br = new BufferedReader(new InputStreamReader(s));
		}

		public Scanner(String file) throws FileNotFoundException {
			br = new BufferedReader(new FileReader(file));
		}

		public String next() throws IOException {
			while (st == null || !st.hasMoreTokens())
				st = new StringTokenizer(br.readLine());
			return st.nextToken();
		}

		public int nextInt() throws IOException {
			return Integer.parseInt(next());
		}

		public long nextLong() throws IOException {
			return Long.parseLong(next());
		}

		public String nextLine() throws IOException {
			return br.readLine();
		}

		public double nextDouble() throws IOException {
			return Double.parseDouble(next());
		}

		public boolean ready() throws IOException {
			return br.ready();
		}

	} Scanner StringTokenizer st; st BufferedReader br; br public Scanner(InputStream s) {
			br = new BufferedReader(new InputStreamReader(s));
		} Scanner {
			br = new BufferedReader(new InputStreamReader(s));
		} br = new BufferedReader(new InputStreamReader(s)) br new BufferedReader(new InputStreamReader(s)) InputStream s s public Scanner(String file) throws FileNotFoundException {
			br = new BufferedReader(new FileReader(file));
		} Scanner {
			br = new BufferedReader(new FileReader(file));
		} br = new BufferedReader(new FileReader(file)) br new BufferedReader(new FileReader(file)) String file file public String next() throws IOException {
			while (st == null || !st.hasMoreTokens())
				st = new StringTokenizer(br.readLine());
			return st.nextToken();
		} next {
			while (st == null || !st.hasMoreTokens())
				st = new StringTokenizer(br.readLine());
			return st.nextToken();
		} while (st == null || !st.hasMoreTokens())
				st = new StringTokenizer(br.readLine()); st == null || !st.hasMoreTokens() st == null st null !st.hasMoreTokens() st.hasMoreTokens() st.hasMoreTokens st st = new StringTokenizer(br.readLine()) st new StringTokenizer(br.readLine()) return st.nextToken(); st.nextToken() st.nextToken st public int nextInt() throws IOException {
			return Integer.parseInt(next());
		} nextInt {
			return Integer.parseInt(next());
		} return Integer.parseInt(next()); Integer.parseInt(next()) Integer.parseInt Integer next() next public long nextLong() throws IOException {
			return Long.parseLong(next());
		} nextLong {
			return Long.parseLong(next());
		} return Long.parseLong(next()); Long.parseLong(next()) Long.parseLong Long next() next public String nextLine() throws IOException {
			return br.readLine();
		} nextLine {
			return br.readLine();
		} return br.readLine(); br.readLine() br.readLine br public double nextDouble() throws IOException {
			return Double.parseDouble(next());
		} nextDouble {
			return Double.parseDouble(next());
		} return Double.parseDouble(next()); Double.parseDouble(next()) Double.parseDouble Double next() next public boolean ready() throws IOException {
			return br.ready();
		} ready {
			return br.ready();
		} return br.ready(); br.ready() br.ready br public class Main {

	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		long target = sc.nextLong();
		long base=100;
		int counts=0;
		while(base<target) {
			base+= (base/100);
			counts++;
		}
		System.out.println(counts);
	}

	static class Pair {
		int x;
		int y;

		public Pair(int x, int y) {
			this.x = x;
			this.y = y;
		}

	}

	static class Scanner {
		StringTokenizer st;
		BufferedReader br;

		public Scanner(InputStream s) {
			br = new BufferedReader(new InputStreamReader(s));
		}

		public Scanner(String file) throws FileNotFoundException {
			br = new BufferedReader(new FileReader(file));
		}

		public String next() throws IOException {
			while (st == null || !st.hasMoreTokens())
				st = new StringTokenizer(br.readLine());
			return st.nextToken();
		}

		public int nextInt() throws IOException {
			return Integer.parseInt(next());
		}

		public long nextLong() throws IOException {
			return Long.parseLong(next());
		}

		public String nextLine() throws IOException {
			return br.readLine();
		}

		public double nextDouble() throws IOException {
			return Double.parseDouble(next());
		}

		public boolean ready() throws IOException {
			return br.ready();
		}

	}
} public class Main {

	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		long target = sc.nextLong();
		long base=100;
		int counts=0;
		while(base<target) {
			base+= (base/100);
			counts++;
		}
		System.out.println(counts);
	}

	static class Pair {
		int x;
		int y;

		public Pair(int x, int y) {
			this.x = x;
			this.y = y;
		}

	}

	static class Scanner {
		StringTokenizer st;
		BufferedReader br;

		public Scanner(InputStream s) {
			br = new BufferedReader(new InputStreamReader(s));
		}

		public Scanner(String file) throws FileNotFoundException {
			br = new BufferedReader(new FileReader(file));
		}

		public String next() throws IOException {
			while (st == null || !st.hasMoreTokens())
				st = new StringTokenizer(br.readLine());
			return st.nextToken();
		}

		public int nextInt() throws IOException {
			return Integer.parseInt(next());
		}

		public long nextLong() throws IOException {
			return Long.parseLong(next());
		}

		public String nextLine() throws IOException {
			return br.readLine();
		}

		public double nextDouble() throws IOException {
			return Double.parseDouble(next());
		}

		public boolean ready() throws IOException {
			return br.ready();
		}

	}
} Main
import java.io.*;
import java.util.*;

public class Main {

	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		long target = sc.nextLong();
		long base=100;
		int counts=0;
		while(base<target) {
			base+= (base/100);
			counts++;
		}
		System.out.println(counts);
	}

	static class Pair {
		int x;
		int y;

		public Pair(int x, int y) {
			this.x = x;
			this.y = y;
		}

	}

	static class Scanner {
		StringTokenizer st;
		BufferedReader br;

		public Scanner(InputStream s) {
			br = new BufferedReader(new InputStreamReader(s));
		}

		public Scanner(String file) throws FileNotFoundException {
			br = new BufferedReader(new FileReader(file));
		}

		public String next() throws IOException {
			while (st == null || !st.hasMoreTokens())
				st = new StringTokenizer(br.readLine());
			return st.nextToken();
		}

		public int nextInt() throws IOException {
			return Integer.parseInt(next());
		}

		public long nextLong() throws IOException {
			return Long.parseLong(next());
		}

		public String nextLine() throws IOException {
			return br.readLine();
		}

		public double nextDouble() throws IOException {
			return Double.parseDouble(next());
		}

		public boolean ready() throws IOException {
			return br.ready();
		}

	}
}
