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.math.BigInteger;
													import java.sql.Array;
												    import java.util.ArrayList;
													import java.util.Arrays;
													import java.util.Collection;
													import java.util.Collections;
													import java.util.Comparator;
													import java.util.HashMap;
		import java.util.HashSet;
		import java.util.InputMismatchException;
										
													import java.util.Scanner;
													import java.util.Set;
													import java.util.Stack;
													import java.io.BufferedReader;
													import java.io.IOException;
													import java.io.InputStream;
													import java.io.InputStreamReader;
													import java.util.Scanner;
													import java.util.StringTokenizer;
													import java.util.TreeMap;
													import java.util.TreeSet;
													
													
													
													public class Main {
											
														static int temp=0;
														public static void main(String[] args) {
														FastReader sc=new FastReader();
														
														int n=sc.nextInt();
														int k=sc.nextInt();
														
													
													//	System.out.println(Math.ceil((double)n/(2*k+1)));
														int ans=(int)Math.ceil((double)n/(double)(2*k+1));
														int start=1;
															for(int i=1;i<=n;i++)
														{
															if(n-i-(ans-1)*(2*k+1)<=k)
																{start=i;
																break;
																}
																
															
														}
															System.out.println(ans);
															for(int i=start;i<=n;i+=2*k+1)
															{
																System.out.print(i+" ");
																
																
															}
																		
															
														
														
											
											
														}
										
														
														
							static	long solve(int n,int k,int turned,int N) {
									
									if(turned>=N)return 0;
									if(n<=0)return Integer.MAX_VALUE;
									
									
									return Math.min(solve(n-1,k,turned,N),1+solve(n-2*k,k,turned+Math.min(k, N-n)+Math.max(k, n-0),N));
									
									
								}
											
														
									
														
											static int find(int parent[],int i) {
												
												if(parent[i]==-1)return i;
												
												return parent[i]=find(parent,parent[i]);
												
											}
											static void union(int parent[],int rank[],int s1,int s2) {
												
												if(rank[s1]>=rank[s2]) {
													
													parent[s2]=s1;
													rank[s1]+=rank[s2];
												}
												
												else {
													
													parent[s1]=s2;
													rank[s2]+=rank[s1];
												}
												
												
											}
														
														
														
														
														
														
														
														
														
														
														
											static	int solve(String S,int K) {
													
													if(K<=0)return 0;
													if(S.charAt(K-1)!=S.charAt(K))
													return 1+solve(S,K-1);
													else return solve(S,K-1);
												}
												
												
												
												
						
						static int dfs(int g[][],int r,int c,int n,int m,boolean visited[][],int s,int t) 
							{
								
								if(r==-1||r==n||c==-1||c==m||visited[r][c])return 0;
								//if()return 0;
								temp+=1;
								visited[r][c]=true;
								if(isValid(g,r-1,c,n,m,visited,s))
								 dfs(g,r-1,c,n,m,visited,s,t);
								if(isValid(g,r+1,c,n,m,visited,s))
								dfs(g,r+1,c,n,m,visited,s,t);
								if(isValid(g,r,c-1,n,m,visited,s))
								dfs(g,r,c-1,n,m,visited,s,t);
								if(isValid(g,r,c+1,n,m,visited,s))
								dfs(g,r,c+1,n,m,visited,s,t);
								//visited[r][c]=false;
							return temp;
							}
							
						static	boolean isValid(int g[][],int r,int c,int n,int m,boolean visited[][],int s) {
								if(r==-1||r==n||c==-1||c==m||visited[r][c]||g[r][c]!=s)return false;
								return true;
							}
						
												
													
																							
													
											    static class FastReader {
											        BufferedReader br;
											        StringTokenizer st;
											 
											        public FastReader()
											        {
											            br = new BufferedReader(
											                new InputStreamReader(System.in));
											        }
											 
											        String next()
											        {
											            while (st == null || !st.hasMoreElements()) {
											                try {
											                    st = new StringTokenizer(br.readLine());
											                }
											                catch (IOException e) {
											                    e.printStackTrace();
											                }
											            }
											            return st.nextToken();
											        }
											 
											        int nextInt() { return Integer.parseInt(next()); }
											 
											        long nextLong() { return Long.parseLong(next()); }
											 
											        double nextDouble()
											        {
											            return Double.parseDouble(next());
											        }
											 
											        String nextLine()
											        {
											            String str = "";
											            try {
											                str = br.readLine();
											            }
											            catch (IOException e) {
											                e.printStackTrace();
											            }
											            return str;
											        }
											    }
											 
												
													}