import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.math.BigInteger;
import java.util.Arrays;
import java.util.*;

public class Main{

    //private static Object InputStream;

    public static void main(String args[]) throws IOException {
        // Object input;
        Scanner scan=new Scanner(System.in);
        long P=100;
        long X=scan.nextLong();
        int x=0;
        long it=0;
        while (P<X){
            it= (long) Math.ceil(P/100);
            P= P+it;
            x++;
            //System.out.println(P);
        }
        System.out.println(x);
    }

} import java.io.BufferedReader; BufferedReader java.io import java.io.IOException; IOException java.io import java.io.InputStream; InputStream java.io import java.io.InputStreamReader; InputStreamReader java.io import java.math.BigInteger; BigInteger java.math import java.util.Arrays; Arrays java.util import java.util.*; util.* java public class Main{

    //private static Object InputStream;

    public static void main(String args[]) throws IOException {
        // Object input;
        Scanner scan=new Scanner(System.in);
        long P=100;
        long X=scan.nextLong();
        int x=0;
        long it=0;
        while (P<X){
            it= (long) Math.ceil(P/100);
            P= P+it;
            x++;
            //System.out.println(P);
        }
        System.out.println(x);
    }

} Main public static void main(String args[]) throws IOException {
        // Object input;
        Scanner scan=new Scanner(System.in);
        long P=100;
        long X=scan.nextLong();
        int x=0;
        long it=0;
        while (P<X){
            it= (long) Math.ceil(P/100);
            P= P+it;
            x++;
            //System.out.println(P);
        }
        System.out.println(x);
    } main {
        // Object input;
        Scanner scan=new Scanner(System.in);
        long P=100;
        long X=scan.nextLong();
        int x=0;
        long it=0;
        while (P<X){
            it= (long) Math.ceil(P/100);
            P= P+it;
            x++;
            //System.out.println(P);
        }
        System.out.println(x);
    } Scanner scan=new Scanner(System.in); scan new Scanner(System.in) long P=100; P 100 long X=scan.nextLong(); X scan.nextLong() scan.nextLong scan int x=0; x 0 long it=0; it 0 while (P<X){
            it= (long) Math.ceil(P/100);
            P= P+it;
            x++;
            //System.out.println(P);
        } P<X P X {
            it= (long) Math.ceil(P/100);
            P= P+it;
            x++;
            //System.out.println(P);
        } it= (long) Math.ceil(P/100) it (long) Math.ceil(P/100) Math.ceil Math P/100 P 100 P= P+it P P+it P it x++ x System.out.println(x) System.out.println System.out System System.out x String args[] args public class Main{

    //private static Object InputStream;

    public static void main(String args[]) throws IOException {
        // Object input;
        Scanner scan=new Scanner(System.in);
        long P=100;
        long X=scan.nextLong();
        int x=0;
        long it=0;
        while (P<X){
            it= (long) Math.ceil(P/100);
            P= P+it;
            x++;
            //System.out.println(P);
        }
        System.out.println(x);
    }

} public class Main{

    //private static Object InputStream;

    public static void main(String args[]) throws IOException {
        // Object input;
        Scanner scan=new Scanner(System.in);
        long P=100;
        long X=scan.nextLong();
        int x=0;
        long it=0;
        while (P<X){
            it= (long) Math.ceil(P/100);
            P= P+it;
            x++;
            //System.out.println(P);
        }
        System.out.println(x);
    }

} Main
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.math.BigInteger;
import java.util.Arrays;
import java.util.*;

public class Main{

    //private static Object InputStream;

    public static void main(String args[]) throws IOException {
        // Object input;
        Scanner scan=new Scanner(System.in);
        long P=100;
        long X=scan.nextLong();
        int x=0;
        long it=0;
        while (P<X){
            it= (long) Math.ceil(P/100);
            P= P+it;
            x++;
            //System.out.println(P);
        }
        System.out.println(x);
    }

}
