import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Scanner;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        abc165_b solver = new abc165_b();
        solver.solve(1, in, out);
        out.close();
    }

    static class abc165_b {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            long X = in.nextLong();
            long base = 100;
            long year = 1;
            while (true) {
                base += Math.floor(base / 100);
                if (X <= base) {
                    out.println(year);
                    return;
                } else {
                    year++;
                }
            }
        }

    }
}
 import java.io.OutputStream; OutputStream java.io import java.io.IOException; IOException java.io import java.io.InputStream; InputStream java.io import java.io.PrintWriter; PrintWriter java.io import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        abc165_b solver = new abc165_b();
        solver.solve(1, in, out);
        out.close();
    }

    static class abc165_b {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            long X = in.nextLong();
            long base = 100;
            long year = 1;
            while (true) {
                base += Math.floor(base / 100);
                if (X <= base) {
                    out.println(year);
                    return;
                } else {
                    year++;
                }
            }
        }

    }
} Main public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        abc165_b solver = new abc165_b();
        solver.solve(1, in, out);
        out.close();
    } main {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        abc165_b solver = new abc165_b();
        solver.solve(1, in, out);
        out.close();
    } InputStream inputStream = System.in; inputStream System.in System System.in OutputStream outputStream = System.out; outputStream System.out System System.out Scanner in = new Scanner(inputStream); in new Scanner(inputStream) PrintWriter out = new PrintWriter(outputStream); out new PrintWriter(outputStream) abc165_b solver = new abc165_b(); solver new abc165_b() solver.solve(1, in, out) solver.solve solver 1 in out out.close() out.close out String[] args args static class abc165_b {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            long X = in.nextLong();
            long base = 100;
            long year = 1;
            while (true) {
                base += Math.floor(base / 100);
                if (X <= base) {
                    out.println(year);
                    return;
                } else {
                    year++;
                }
            }
        }

    } abc165_b public void solve(int testNumber, Scanner in, PrintWriter out) {
            long X = in.nextLong();
            long base = 100;
            long year = 1;
            while (true) {
                base += Math.floor(base / 100);
                if (X <= base) {
                    out.println(year);
                    return;
                } else {
                    year++;
                }
            }
        } solve {
            long X = in.nextLong();
            long base = 100;
            long year = 1;
            while (true) {
                base += Math.floor(base / 100);
                if (X <= base) {
                    out.println(year);
                    return;
                } else {
                    year++;
                }
            }
        } long X = in.nextLong(); X in.nextLong() in.nextLong in long base = 100; base 100 long year = 1; year 1 while (true) {
                base += Math.floor(base / 100);
                if (X <= base) {
                    out.println(year);
                    return;
                } else {
                    year++;
                }
            } true {
                base += Math.floor(base / 100);
                if (X <= base) {
                    out.println(year);
                    return;
                } else {
                    year++;
                }
            } base += Math.floor(base / 100) base Math.floor(base / 100) Math.floor Math base / 100 base 100 if (X <= base) {
                    out.println(year);
                    return;
                } else {
                    year++;
                } X <= base X base {
                    out.println(year);
                    return;
                } out.println(year) out.println out year return; {
                    year++;
                } year++ year int testNumber testNumber Scanner in in PrintWriter out out public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        abc165_b solver = new abc165_b();
        solver.solve(1, in, out);
        out.close();
    }

    static class abc165_b {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            long X = in.nextLong();
            long base = 100;
            long year = 1;
            while (true) {
                base += Math.floor(base / 100);
                if (X <= base) {
                    out.println(year);
                    return;
                } else {
                    year++;
                }
            }
        }

    }
} public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        abc165_b solver = new abc165_b();
        solver.solve(1, in, out);
        out.close();
    }

    static class abc165_b {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            long X = in.nextLong();
            long base = 100;
            long year = 1;
            while (true) {
                base += Math.floor(base / 100);
                if (X <= base) {
                    out.println(year);
                    return;
                } else {
                    year++;
                }
            }
        }

    }
} Main
import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Scanner;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        abc165_b solver = new abc165_b();
        solver.solve(1, in, out);
        out.close();
    }

    static class abc165_b {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            long X = in.nextLong();
            long base = 100;
            long year = 1;
            while (true) {
                base += Math.floor(base / 100);
                if (X <= base) {
                    out.println(year);
                    return;
                } else {
                    year++;
                }
            }
        }

    }
}

