Problem: Long story short, shashlik is Miroslav's favorite food. Shashlik is prepared on several skewers simultaneously. There are two states for each skewer: initial and turned over.

This time Miroslav laid out n skewers parallel to each other, and enumerated them with consecutive integers from 1 to n in order from left to right. For better cooking, he puts them quite close to each other, so when he turns skewer number i, it leads to turning k closest skewers from each side of the skewer i, that is, skewers number i - k, i - k + 1, ..., i - 1, i + 1, ..., i + k - 1, i + k (if they exist). 

For example, let n = 6 and k = 1. When Miroslav turns skewer number 3, then skewers with numbers 2, 3, and 4 will come up turned over. If after that he turns skewer number 1, then skewers number 1, 3, and 4 will be turned over, while skewer number 2 will be in the initial position (because it is turned again).

As we said before, the art of cooking requires perfect timing, so Miroslav wants to turn over all n skewers with the minimal possible number of actions. For example, for the above example n = 6 and k = 1, two turnings are sufficient: he can turn over skewers number 2 and 5.

Help Miroslav turn over all n skewers.

Input

The first line contains two integers n and k (1 ≤ n ≤ 1000, 0 ≤ k ≤ 1000) — the number of skewers and the number of skewers from each side that are turned in one step.

Output

The first line should contain integer l — the minimum number of actions needed by Miroslav to turn over all n skewers. After than print l integers from 1 to n denoting the number of the skewer that is to be turned over at the corresponding step.

Examples

Input

7 2


Output

2
1 6 


Input

5 1


Output

2
1 4 

Note

In the first example the first operation turns over skewers 1, 2 and 3, the second operation turns over skewers 4, 5, 6 and 7.

In the second example it is also correct to turn over skewers 2 and 5, but turning skewers 2 and 4, or 1 and 5 are incorrect solutions because the skewer 3 is in the initial state after these operations.

Solution (in JAVA):

Solution:
import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.io.BufferedWriter;
import java.io.Writer;
import java.io.OutputStreamWriter;
import java.util.InputMismatchException;
import java.io.IOException;
import java.util.LinkedList;
import java.io.InputStream;

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

  static class TaskB {
    public void solve(int testNumber, InputReader in, OutputWriter out) {
      int n = in.nextInt();
      int k = in.nextInt();
      if (k > n - 1) {
        out.println(1);
        out.println(1);
        return;
      }
      if (k == 0) {
        out.println(n);
        for (int i = 0; i < n; i++) {
          out.print(i + 1);
          out.print(' ');
        }
        out.println();
        return;
      }

      int mod = 2 * k + 1;
      int r = n % mod;
      int start;
      if (r == 0 || r > k) {
        start = k;
      } else {
        start = r - 1;
      }
      LinkedList<Integer> moves = new LinkedList<>();
      moves.add(start);
      int i = start + k + 1;
      while (i < n) {
        moves.add(i + k);
        i += k + k + 1;
      }
      out.println(moves.size());
      for (Integer q : moves) {
        out.print(q + 1);
        out.print(' ');
      }
      out.println();
    }

  }

  static class InputReader {
    private InputStream is;
    private byte[] buff = new byte[8 * 1024];
    private int curChar;
    private int numChars;

    public InputReader(InputStream is) {
      this.is = is;
    }

    public int read() {
      if (numChars == -1) throw new InputMismatchException();
      if (curChar >= numChars) {
        curChar = 0;
        try {
          numChars = is.read(buff);
        } catch (IOException e) {
          throw new InputMismatchException();
        }
        if (numChars <= 0) return -1;
      }
      return buff[curChar++];
    }

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

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

  }

  static class OutputWriter {
    private final PrintWriter writer;

    public OutputWriter(OutputStream outputStream) {
      writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(outputStream)));
    }

    public OutputWriter(Writer writer) {
      this.writer = new PrintWriter(writer);
    }

    public void print(Object... objects) {
      for (int i = 0; i < objects.length; i++) {
        if (i != 0) writer.print(' ');
        writer.print(objects[i]);
      }
    }

    public void println(Object... objects) {
      print(objects);
      writer.println();
    }

    public void close() {
      writer.close();
    }

  }
}