// 問題URL
// https://atcoder.jp/contests/abc165/tasks/abc165_b

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        //コード
        Scanner scanner = new Scanner(System.in);
        Long n = scanner.nextLong();

        //System.out.println(n / 100L);
        Long count = 0L;
        Long result = 100L;
        for(;;) {
            result += ((long)Math.floor(result*0.01));
            count++;
            if(result >= n) break;;
        }


        System.out.println(count);
    }
} import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args) {
        //コード
        Scanner scanner = new Scanner(System.in);
        Long n = scanner.nextLong();

        //System.out.println(n / 100L);
        Long count = 0L;
        Long result = 100L;
        for(;;) {
            result += ((long)Math.floor(result*0.01));
            count++;
            if(result >= n) break;;
        }


        System.out.println(count);
    }
} Main public static void main(String[] args) {
        //コード
        Scanner scanner = new Scanner(System.in);
        Long n = scanner.nextLong();

        //System.out.println(n / 100L);
        Long count = 0L;
        Long result = 100L;
        for(;;) {
            result += ((long)Math.floor(result*0.01));
            count++;
            if(result >= n) break;;
        }


        System.out.println(count);
    } main {
        //コード
        Scanner scanner = new Scanner(System.in);
        Long n = scanner.nextLong();

        //System.out.println(n / 100L);
        Long count = 0L;
        Long result = 100L;
        for(;;) {
            result += ((long)Math.floor(result*0.01));
            count++;
            if(result >= n) break;;
        }


        System.out.println(count);
    } Scanner scanner = new Scanner(System.in); scanner new Scanner(System.in) Long n = scanner.nextLong(); n scanner.nextLong() scanner.nextLong scanner Long count = 0L; count 0L Long result = 100L; result 100L for(;;) {
            result += ((long)Math.floor(result*0.01));
            count++;
            if(result >= n) break;;
        } ; {
            result += ((long)Math.floor(result*0.01));
            count++;
            if(result >= n) break;;
        } {
            result += ((long)Math.floor(result*0.01));
            count++;
            if(result >= n) break;;
        } result += ((long)Math.floor(result*0.01)) result ((long)Math.floor(result*0.01)) Math.floor Math result*0.01 result 0.01 count++ count if(result >= n) break; result >= n result n break; System.out.println(count) System.out.println System.out System System.out count String[] args args public class Main {
    public static void main(String[] args) {
        //コード
        Scanner scanner = new Scanner(System.in);
        Long n = scanner.nextLong();

        //System.out.println(n / 100L);
        Long count = 0L;
        Long result = 100L;
        for(;;) {
            result += ((long)Math.floor(result*0.01));
            count++;
            if(result >= n) break;;
        }


        System.out.println(count);
    }
} public class Main {
    public static void main(String[] args) {
        //コード
        Scanner scanner = new Scanner(System.in);
        Long n = scanner.nextLong();

        //System.out.println(n / 100L);
        Long count = 0L;
        Long result = 100L;
        for(;;) {
            result += ((long)Math.floor(result*0.01));
            count++;
            if(result >= n) break;;
        }


        System.out.println(count);
    }
} Main
// 問題URL
// https://atcoder.jp/contests/abc165/tasks/abc165_b

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        //コード
        Scanner scanner = new Scanner(System.in);
        Long n = scanner.nextLong();

        //System.out.println(n / 100L);
        Long count = 0L;
        Long result = 100L;
        for(;;) {
            result += ((long)Math.floor(result*0.01));
            count++;
            if(result >= n) break;;
        }


        System.out.println(count);
    }
}
