import java.util.*;

public class Main {
	public static void main(String[] args) {
	    Scanner sc = new Scanner(System.in);
        long target = Long.valueOf(sc.next());
        long yen = 100;
        int count = 0;

        for(;;) {
            yen *= 1.01;
            count++;
            if(yen >= target) break;
        }
        System.out.println(count);
	}
} import java.util.*; util.* java public class Main {
	public static void main(String[] args) {
	    Scanner sc = new Scanner(System.in);
        long target = Long.valueOf(sc.next());
        long yen = 100;
        int count = 0;

        for(;;) {
            yen *= 1.01;
            count++;
            if(yen >= target) break;
        }
        System.out.println(count);
	}
} Main public static void main(String[] args) {
	    Scanner sc = new Scanner(System.in);
        long target = Long.valueOf(sc.next());
        long yen = 100;
        int count = 0;

        for(;;) {
            yen *= 1.01;
            count++;
            if(yen >= target) break;
        }
        System.out.println(count);
	} main {
	    Scanner sc = new Scanner(System.in);
        long target = Long.valueOf(sc.next());
        long yen = 100;
        int count = 0;

        for(;;) {
            yen *= 1.01;
            count++;
            if(yen >= target) break;
        }
        System.out.println(count);
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) long target = Long.valueOf(sc.next()); target Long.valueOf(sc.next()) Long.valueOf Long sc.next() sc.next sc long yen = 100; yen 100 int count = 0; count 0 for(;;) {
            yen *= 1.01;
            count++;
            if(yen >= target) break;
        } ; {
            yen *= 1.01;
            count++;
            if(yen >= target) break;
        } {
            yen *= 1.01;
            count++;
            if(yen >= target) break;
        } yen *= 1.01 yen 1.01 count++ count if(yen >= target) break; yen >= target yen target 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) {
	    Scanner sc = new Scanner(System.in);
        long target = Long.valueOf(sc.next());
        long yen = 100;
        int count = 0;

        for(;;) {
            yen *= 1.01;
            count++;
            if(yen >= target) break;
        }
        System.out.println(count);
	}
} public class Main {
	public static void main(String[] args) {
	    Scanner sc = new Scanner(System.in);
        long target = Long.valueOf(sc.next());
        long yen = 100;
        int count = 0;

        for(;;) {
            yen *= 1.01;
            count++;
            if(yen >= target) break;
        }
        System.out.println(count);
	}
} Main
import java.util.*;

public class Main {
	public static void main(String[] args) {
	    Scanner sc = new Scanner(System.in);
        long target = Long.valueOf(sc.next());
        long yen = 100;
        int count = 0;

        for(;;) {
            yen *= 1.01;
            count++;
            if(yen >= target) break;
        }
        System.out.println(count);
	}
}