Little Lesha loves listening to music via his smartphone. But the smartphone doesn't have much memory, so Lesha listens to his favorite songs in a well-known social network InTalk.

Unfortunately, internet is not that fast in the city of Ekaterinozavodsk and the song takes a lot of time to download. But Lesha is quite impatient. The song's duration is T seconds. Lesha downloads the first S seconds of the song and plays it. When the playback reaches the point that has not yet been downloaded, Lesha immediately plays the song from the start (the loaded part of the song stays in his phone, and the download is continued from the same place), and it happens until the song is downloaded completely and Lesha listens to it to the end. For q seconds of real time the Internet allows you to download q - 1 seconds of the track.

Tell Lesha, for how many times he will start the song, including the very first start.

Input

The single line contains three integers T, S, q (2 ≤ q ≤ 104, 1 ≤ S < T ≤ 105).

Output

Print a single integer — the number of times the song will be restarted.

Examples

Input

5 2 2


Output

2


Input

5 4 7


Output

1


Input

6 2 3


Output

1

Note

In the first test, the song is played twice faster than it is downloaded, which means that during four first seconds Lesha reaches the moment that has not been downloaded, and starts the song again. After another two seconds, the song is downloaded completely, and thus, Lesha starts the song twice.

In the second test, the song is almost downloaded, and Lesha will start it only once.

In the third sample test the download finishes and Lesha finishes listening at the same moment. Note that song isn't restarted in this case.
import javafx.util.Pair;

import java.io.*;
import java.util.*;
import java.util.function.Function;

public class Main {
    private final static InputReader ir = new InputReader(System.in);
    private final static OutputWriter ow = new OutputWriter(System.out);
    private final static int INF = Integer.MAX_VALUE;
    private final static int NINF = Integer.MIN_VALUE;
    private final static double PI = Math.PI;

    public static void main(String[] args) throws IOException {
        try {
            task();
        } finally {
            boolean exc = false;
            try {
                ir.close();
            } catch (IOException e) {
                e.printStackTrace();
                exc = true;
            }
            try {
                ow.close();
            } catch (IOException e) {
                e.printStackTrace();
                exc = true;
            }
            if (exc) System.exit(1);
        }
    }

    private static void task() throws IOException {
        int T = ir.nextInt();
        int S = ir.nextInt();
        int q = ir.nextInt();

        int cnt = 0;
        int load = S;
        int lis = 1;
        for (int i = 1; lis != T; ++i) {
            //ow.println(load + " " + lis);
            ++lis;
            if (i % q != 0) {
                ++load;
            }
            if (lis > load) {
                lis = 1;
                cnt++;
            }

        }
        ow.print(cnt + 1);
    }

    private static int max(int... objects) {
        if (objects.length == 0)
            throw new IllegalArgumentException("objects.length == 0");
        int max = objects[0];
        for (int i = 1; i < objects.length; ++i) {
            if (max < objects[i])
                max = objects[i];
        }
        return max;
    }

    private static int min(int... objects) {
        if (objects.length == 0)
            throw new IllegalArgumentException("objects.length == 0");
        int min = objects[0];
        for (int i = 1; i < objects.length; ++i) {
            if (min > objects[i])
                min = objects[i];
        }
        return min;
    }

    private static long pow(int x, int n) {
        if (x == 0) return 0;
        if (x == 1 || n == 0) return 1;
        if (x == 2) return x << (n - 1);
        if (n == 1) return x;
        long t = pow(x, n / 2);
        if (n % 2 == 0) return t * t;
        else return t * t * x;
    }

    private static double pow(double x, int n) {
        if (x == 0.0) return 0;
        if (x == 1.0 || n == 0) return 1;
        if (n == 1) return x;
        double t = pow(x, n / 2);
        if (n % 2 == 0) return t * t;
        else return t * t * x;
    }

    private static int abs(int a) {
        return (a >= 0 ? a : -a);
    }
}

class SQRTDecomposition {
    private int[] array;
    private int len;
    private int[] max;
    private int[] min;

    public SQRTDecomposition(int[] arr, boolean useIt) {
        if (useIt)
            array = arr;
        else {
            array = new int[arr.length];
            System.arraycopy(arr, 0, array, 0, arr.length);
        }
        len = (int) Math.sqrt(array.length) + 1;
        max = new int[len];
        min = new int[len];
        for (int i = 0; i < array.length; ++i) {
            max[i / len] = min[i / len] = array[i];
        }
        for (int i = 0; i < array.length; ++i) {
            max[i / len] = Math.max(max[i / len], array[i]);
            min[i / len] = Math.min(min[i / len], array[i]);
        }
    }

    public int get(int i) {
        if (i <= 0 || i >= array.length)
            throw new IndexOutOfBoundsException("Index: " + i);
        return array[i];
    }

    public int length() {
        return array.length;
    }

    public int max(int l, int r) {
        int cl = l / len, cr = r / len;
        int m = array[l];
        if (cl == cr) {
            for (int i = l; i <= r; ++i) {
                if (array[i] > m) m = array[i];
            }
        } else {
            for (int i = l, end = (cl + 1) * len - 1; i <= end; ++i)
                if (array[i] > m) m = array[i];
            for (int i = cl + 1; i <= cr - 1; ++i)
                if (max[i] > m) m = max[i];
            for (int i = cr * len; i <= r; ++i)
                if (array[i] > m) m = array[i];
        }
        return m;
    }

    public int min(int l, int r) {
        int cl = l / len, cr = r / len;
        int m = array[l];
        if (cl == cr) {
            for (int i = l; i <= r; ++i) {
                if (array[i] < m) m = array[i];
            }
        } else {
            for (int i = l, end = (cl + 1) * len - 1; i <= end; ++i)
                if (array[i] < m) m = array[i];
            for (int i = cl + 1; i <= cr - 1; ++i)
                if (min[i] < m) m = min[i];
            for (int i = cr * len; i <= r; ++i)
                if (array[i] < m) m = array[i];
        }
        return m;
    }
}

class InputReader implements AutoCloseable {
    private final InputStream in;
    private int capacity;
    private byte[] buffer;
    private int len = 0;
    private int cur = 0;

    public InputReader(InputStream stream) {
        this(stream, 100_000);
    }

    public InputReader(InputStream stream, int capacity) {
        this.in = stream;
        this.capacity = capacity;
        buffer = new byte[capacity];
    }

    private boolean update() {
        if (cur >= len) {
            try {
                cur = 0;
                len = in.read(buffer, 0, capacity);
                if (len <= 0)
                    return false;
            } catch (IOException e) {
                throw new InputMismatchException();
            }
        }
        return true;
    }

    private int read() {
        if (update())
            return buffer[cur++];
        else return -1;
    }

    public boolean isEmpty() {
        return !update();
    }

    private boolean isSpace(int c) {
        return c == '\n' || c == '\t' || c == '\r' || c == ' ';
    }

    private boolean isEscape(int c) {
        return c == '\n' || c == '\t' || c == '\r' || c == -1;
    }

    private int readSkipSpace() {
        int c;
        do {
            c = read();
        } while (isSpace(c));
        return c;
    }

    public int nextInt() {
        int c = readSkipSpace();
        if (c < 0)
            throw new InputMismatchException();
        int sgn = 1;
        if (c == '-') {
            sgn = -1;
            c = read();
        }
        int res = 0;
        do {
            if (c == -1) break;
            if (c < '0' || c > '9')
                throw new InputMismatchException();
            res = res * 10 + c - '0';
            if (res < 0)
                throw new InputMismatchException();
            c = read();
        } while (!isSpace(c));
        res *= sgn;
        return res;
    }

    public int[] getAllInts() {
        List<Integer> list = new LinkedList<>();
        while (true) {
            try {
                int t = nextInt();
                list.add(t);
            } catch (InputMismatchException e) {
                break;
            }
        }
        int[] a = new int[list.size()];
        Iterator<Integer> it = list.iterator();
        for (int i = 0; it.hasNext(); ++i)
            a[i] = it.next();
        return a;
    }

    public int[] getIntArray1D(int n) {
        int[] array = new int[n];
        for (int i = 0; i < n; ++i) {
            array[i] = nextInt();
        }
        return array;
    }

    public int[][] getIntArray2D(int n, int m) {
        int[][] array = new int[n][m];
        for (int i = 0; i < n; ++i) {
            for (int j = 0; j < m; ++j)
                array[i][j] = nextInt();
        }
        return array;
    }

    public long nextLong() {
        int c = readSkipSpace();
        if (c < 0)
            throw new InputMismatchException();
        int sgn = 1;
        if (c == '-') {
            sgn = -1;
            c = read();
        }
        long res = 0;
        do {
            if (c == -1) break;
            if (c < '0' || c > '9')
                throw new InputMismatchException();
            res = res * 10 + c - '0';
            if (res < 0)
                throw new InputMismatchException();
            c = read();
        } while (!isSpace(c));
        res *= sgn;
        return res;
    }

    public long[] getAllLongs() {
        List<Long> list = new LinkedList<>();
        while (true) {
            try {
                long t = nextLong();
                list.add(t);
            } catch (InputMismatchException e) {
                break;
            }
        }
        long[] a = new long[list.size()];
        Iterator<Long> it = list.iterator();
        for (int i = 0; it.hasNext(); ++i)
            a[i] = it.next();
        return a;
    }

    public long[] getLongArray1D(int n) {
        long[] array = new long[n];
        for (int i = 0; i < n; ++i) {
            array[i] = nextLong();
        }
        return array;
    }

    public long[][] getLongArray2D(int n, int m) {
        long[][] array = new long[n][m];
        for (int i = 0; i < n; ++i) {
            for (int j = 0; j < m; ++j)
                array[i][j] = nextLong();
        }
        return array;
    }

    public int nextChar() {
        int c = readSkipSpace();
        if (c < 0)
            throw new InputMismatchException();
        return c;
    }

    public String nextLine(int initialCapacity) {
        StringBuilder res = new StringBuilder(initialCapacity);
        int c = readSkipSpace();
        do {
            res.append((char) (c));
            c = read();
        } while (!isEscape(c));
        return res.toString();
    }

    @Override
    public void close() throws IOException {
        in.close();
    }
}

class OutputWriter implements Flushable, AutoCloseable {
    private byte[] buf;
    private final int capacity;
    private int count;
    private OutputStream out;

    public OutputWriter(OutputStream stream) {
        this(stream, 10_000);
    }

    public OutputWriter(OutputStream stream, int capacity) {
        if (capacity < 0)
            throw new IllegalArgumentException("capacity < 0");
        out = stream;
        this.capacity = capacity;
        if (capacity != 0) {
            buf = new byte[capacity];
        }
    }

    public void write(int b) throws IOException {
        if (capacity != 0) {
            if (count >= capacity)
                flushBuffer();
            buf[count++] = (byte) b;
        } else {
            out.write(b);
        }
    }

    public void write(byte[] bytes, int off, int len) throws IOException {
        if (capacity != 0) {
            if (len >= capacity) {
                flushBuffer();
                out.write(bytes, off, len);
                return;
            }
            if (len > capacity - count)
                flushBuffer();
            System.arraycopy(bytes, off, buf, count, len);
            count += len;
        } else out.write(bytes, off, len);
    }

    public void write(byte[] bytes) throws IOException {
        write(bytes, 0, bytes.length);
    }

    public void println() throws IOException {
        print("\n");
    }

    public void print(Object object) throws IOException {
        write(String.valueOf(object).getBytes());
    }

    public void println(Object object) throws IOException {
        print(object);
        println();
    }

    public void print(int... ints) throws IOException {
        print(" ", ints);
    }

    public void println(int... ints) throws IOException {
        print(ints);
        println();
    }

    public void println(String separator, int... ints) throws IOException {
        print(separator, ints);
        println();
    }

    public void print(String separator, int... ints) throws IOException {
        if (ints.length == 0) throw new IllegalArgumentException("ints.length == 0");
        for (int i = 0; i < ints.length; ++i) {
            if (i != 0) print(separator);
            print(ints[i]);
        }
    }

    private void flushBuffer() throws IOException {
        if (count > 0) {
            out.write(buf, 0, count);
            count = 0;
        }
    }

    @Override
    public void flush() throws IOException {
        flushBuffer();
        out.flush();
    }

    @Override
    public void close() throws IOException {
        flush();
        out.close();
    }
}
/*
class InputReader implements AutoCloseable {
    private final InputStream in;
    private int capacity;
    private byte[] buffer;
    private int len = 0;
    private int cur = 0;

    public InputReader(InputStream stream) {
        this(stream, 100_000);
    }

    public InputReader(InputStream stream, int capacity) {
        this.in = stream;
        this.capacity = capacity;
        buffer = new byte[capacity];
    }

    private int read() {
        if (cur >= len) {
            try {
                cur = 0;
                len = in.read(buffer, 0, capacity);
                if (len <= 0)
                    return -1;
            } catch (IOException e) {
                throw new InputMismatchException();
            }
        }
        return buffer[cur++];
    }

    private boolean isSpace(int c) {
        return c == ' ' || isEscape(c);
    }

    private boolean isEscape(int c) {
        return c == '\n' || c == '\t' || c == '\r' || c == -1;
    }

    private int readSkipSpace() {
        int c;
        do {
            c = read();
        } while (isSpace(c));
        return c;
    }

    int nextInt() {
        int c = readSkipSpace();
        int sgn = 1;
        if (c == '-') {
            sgn = -1;
            c = read();
        }
        int res = 0;
        do {
            if (c < '0' || c > '9')
                throw new InputMismatchException();
            res = res * 10 + c - '0';
            if (res < 0)
                throw new InputMismatchException();
            c = read();
        } while (!isSpace(c));
        res *= sgn;
        return res;
    }

    public long nextLong() {
        int c = readSkipSpace();
        int sgn = 1;
        if (c == '-') {
            sgn = -1;
            c = read();
        }
        long res = 0;
        do {
            if (c < '0' || c > '9')
                throw new InputMismatchException();
            res = res * 10 + c - '0';
            if (res < 0)
                throw new InputMismatchException();
            c = read();
        } while (!isSpace(c));
        res *= sgn;
        return res;
    }

    int nextChar() {
        return readSkipSpace();
    }

    String nextLine(int initialCapacity) {
        StringBuilder res = new StringBuilder(initialCapacity);
        int c = readSkipSpace();
        do {
            res.append((char) (c));
            c = read();
        } while (!isEscape(c));
        return res.toString();
    }

    @Override
    public void close() throws IOException {
        in.close();
    }
}

class OutputWriter implements Flushable, AutoCloseable {
    private byte[] buf;
    private int capacity;
    private int count;
    private OutputStream out;

    public OutputWriter(OutputStream stream) {
        out = stream;
        capacity = 10_000;
        buf = new byte[capacity];
    }

    public OutputWriter(OutputStream stream, int capacity) {
        if (capacity <= 0)
            throw new IllegalArgumentException("capacity <= 0");
        out = stream;
        this.capacity = capacity;
        buf = new byte[capacity];
    }

    public void write(int b) throws IOException {
        if (count >= buf.length)
            flushBuffer();
        buf[count++] = (byte) b;
    }

    public void write(byte[] bytes, int off, int len) throws IOException {
        if (len >= buf.length) {
            flushBuffer();
            out.write(bytes, off, len);
            return;
        }
        if (len > buf.length - count)
            flushBuffer();
        System.arraycopy(bytes, off, buf, count, len);
        count += len;
    }

    public void write(byte[] bytes) throws IOException {
        write(bytes, 0, bytes.length);
    }

    public void print(String str) throws IOException {
        write(str.getBytes());
    }

    public void println() throws IOException {
        print("\n");
    }

    public void print(Object object) throws IOException {
        print(object.toString());
    }

    public void println(Object object) throws IOException {
        print(object.toString());
        println();
    }

    public void print(int... ints) throws IOException {
        print(" ", ints);
    }

    public void println(int... ints) throws IOException {
        print(ints);
        println();
    }

    public void println(String separator, int... ints) throws IOException {
        print(separator, ints);
        println();
    }

    public void print(String separator, int... ints) throws IOException {
        if (ints.length == 0) throw new IllegalArgumentException("ints.length == 0");
        for (int i = 0; i < ints.length; ++i) {
            if (i != 0) print(separator);
            print(ints[i]);
        }
    }

    private void flushBuffer() throws IOException {
        if (count > 0) {
            out.write(buf, 0, count);
            count = 0;
        }
    }

    @Override
    public void flush() throws IOException {
        flushBuffer();
        out.flush();
    }

    @Override
    public void close() throws IOException {
        flush();
        out.close();
    }
}

*/


