You are given a grid, consisting of 2 rows and n columns. Each cell of this grid should be colored either black or white.

Two cells are considered neighbours if they have a common border and share the same color. Two cells A and B belong to the same component if they are neighbours, or if there is a neighbour of A that belongs to the same component with B.

Let's call some bicoloring beautiful if it has exactly k components.

Count the number of beautiful bicolorings. The number can be big enough, so print the answer modulo 998244353.

Input

The only line contains two integers n and k (1 ≤ n ≤ 1000, 1 ≤ k ≤ 2n) — the number of columns in a grid and the number of components required.

Output

Print a single integer — the number of beautiful bicolorings modulo 998244353.

Examples

Input

3 4


Output

12


Input

4 1


Output

2


Input

1 2


Output

2

Note

One of possible bicolorings in sample 1:

<image>
import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.FileNotFoundException;
import java.io.File;
import java.util.StringTokenizer;
import java.io.Writer;
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.InputStream;

/**
 * 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;
    InputReader in = new InputReader(inputStream);
    OutputWriter out = new OutputWriter(outputStream);
    TaskD solver = new TaskD();
    solver.solve(1, in, out);
    out.close();
  }

  static class TaskD extends SimpleSavingChelperSolution {
    int MOD = 998244353;
    int[][] componentChanges = {
        {0, 1, 1, 1}, //00
        {0, 0, 2, 0}, //01
        {0, 2, 0, 0}, //10
        {1, 1, 1, 0}, //11
    };

    public void solve(int testNumber, InputReader in, OutputWriter out) {
      wrapSolve(testNumber, in, out);
    }


    public void solve(int testNumber) {
      int n = in.nextInt();
      int colors = in.nextInt();

      int[][][] dp = new int[n][colors + 10][4];

      dp[0][1][0]++;
      dp[0][2][1]++;
      dp[0][2][2]++;
      dp[0][1][3]++;

      for (int i = 0; i < n - 1; i++) {
        for (int k = 0; k <= colors; k++) {
          for (int curMask = 0; curMask < 4; curMask++) {
            for (int nextMask = 0; nextMask < 4; nextMask++) {
              int newK = k + componentChanges[curMask][nextMask];
              if (newK > colors) {
                continue;
              }

              dp[i + 1][newK][nextMask] += dp[i][k][curMask];
              dp[i + 1][newK][nextMask] %= MOD;
            }
          }
        }
      }

      int result = 0;
      for (int i = 0; i < 4; i++) {
        result += dp[n - 1][colors][i];
        result %= MOD;
      }
      out.println(result);
    }

  }

  static abstract class SimpleSavingChelperSolution extends SavingChelperSolution {

    public String processOutputPreCheck(int testNumber, String output) {
      return output;
    }


    public String processOutputPostCheck(int testNumber, String output) {
      return output;
    }

  }

  static class InputReader {
    private BufferedReader br;
    private StringTokenizer in;

    public InputReader(String fileName) {
      try {
        br = new BufferedReader(new FileReader(fileName));
      } catch (IOException e) {
        throw new RuntimeException(e);
      }
    }

    public InputReader(InputStream inputStream) {
      br = new BufferedReader(new InputStreamReader(inputStream));
    }

    private boolean hasMoreTokens() {
      while (in == null || !in.hasMoreTokens()) {
        String s = nextLine();
        if (s == null) {
          return false;
        }
        in = new StringTokenizer(s);
      }
      return true;
    }

    public String nextString() {
      return hasMoreTokens() ? in.nextToken() : null;
    }

    public String nextLine() {
      try {
        in = null;
        return br.readLine();
      } catch (Exception e) {
        e.printStackTrace();
        return null;
      }
    }

    public int nextInt() {
      return Integer.parseInt(nextString());
    }

  }

  static abstract class SavingChelperSolution {
    protected int testNumber;
    public InputReader in;
    public OutputWriter out;
    private OutputWriter toFile;
    private boolean local = new File("chelper.properties").exists();
    public OutputWriter debug;

    {
      if (local) {
        debug = new OutputWriter(System.err);
      } else {
        debug = new OutputWriter(new OutputStream() {

          public void write(int b) {
          }
        });
      }
    }

    public SavingChelperSolution() {
      try {
        toFile = new OutputWriter("last_test_output.txt");
      } catch (FileNotFoundException e) {
        throw new RuntimeException(e);
      }
    }

    public abstract void solve(int testNumber);

    public abstract String processOutputPreCheck(int testNumber, String output);

    public abstract String processOutputPostCheck(int testNumber, String output);

    public void wrapSolve(int testNumber, InputReader in, OutputWriter out) {
      this.testNumber = testNumber;

      ByteArrayOutputStream substituteOutContents = new ByteArrayOutputStream();
      OutputWriter substituteOut = new OutputWriter(substituteOutContents);

      this.in = in;
      this.out = substituteOut;

      solve(testNumber);
      substituteOut.flush();

      String result = substituteOutContents.toString();

      result = processOutputPreCheck(testNumber, result);
      out.print(result);
      out.flush();

      if (local) {
        debug.flush();

        result = processOutputPostCheck(testNumber, result);
        toFile.print(result);
        toFile.flush();
      }
    }

  }

  static class OutputWriter extends PrintWriter {

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

    public OutputWriter(String fileName) throws FileNotFoundException {
      super(fileName);
    }

    public OutputWriter(OutputStream outputStream) {
      super(outputStream);
    }

    public OutputWriter(Writer writer) {
      super(writer);
    }

  }
}

