Problem: Merge sort is a well-known sorting algorithm. The main function that sorts the elements of array a with indices from [l, r) can be implemented as follows:

  1. If the segment [l, r) is already sorted in non-descending order (that is, for any i such that l ≤ i < r - 1 a[i] ≤ a[i + 1]), then end the function call; 
  2. Let <image>; 
  3. Call mergesort(a, l, mid); 
  4. Call mergesort(a, mid, r); 
  5. Merge segments [l, mid) and [mid, r), making the segment [l, r) sorted in non-descending order. The merge algorithm doesn't call any other functions. 



The array in this problem is 0-indexed, so to sort the whole array, you need to call mergesort(a, 0, n).

The number of calls of function mergesort is very important, so Ivan has decided to calculate it while sorting the array. For example, if a = {1, 2, 3, 4}, then there will be 1 call of mergesort — mergesort(0, 4), which will check that the array is sorted and then end. If a = {2, 1, 3}, then the number of calls is 3: first of all, you call mergesort(0, 3), which then sets mid = 1 and calls mergesort(0, 1) and mergesort(1, 3), which do not perform any recursive calls because segments (0, 1) and (1, 3) are sorted.

Ivan has implemented the program that counts the number of mergesort calls, but now he needs to test it. To do this, he needs to find an array a such that a is a permutation of size n (that is, the number of elements in a is n, and every integer number from [1, n] can be found in this array), and the number of mergesort calls when sorting the array is exactly k.

Help Ivan to find an array he wants!

Input

The first line contains two numbers n and k (1 ≤ n ≤ 100000, 1 ≤ k ≤ 200000) — the size of a desired permutation and the number of mergesort calls required to sort it.

Output

If a permutation of size n such that there will be exactly k calls of mergesort while sorting it doesn't exist, output  - 1. Otherwise output n integer numbers a[0], a[1], ..., a[n - 1] — the elements of a permutation that would meet the required conditions. If there are multiple answers, print any of them.

Examples

Input

3 3


Output

2 1 3 

Input

4 1


Output

1 2 3 4 

Input

5 6


Output

-1

Solution (in JAVA):

Solution:
import java.io.*;
import java.math.*;
import java.util.*;

public class D_mergeSort {
    public static void main(String[] args) throws IOException {
        FastScanner sc = new FastScanner(System.in);
        PrintWriter pw = new PrintWriter(System.out);
        
        int n = sc.nextInt();
        int k = sc.nextInt();
        if (k % 2 == 0 || k > 2*n) {
        	pw.println(-1);
        }
        else {
        int[] arr = new int[n];
        for (int i = 0; i < arr.length; i++) {
        	arr[i] = i+1;
        }
        List<Integer> list = new ArrayList<>();
        list.add(0);
        list.add(n);
        int count = 1;
        hi:
        while (count < k) {
        	int size = list.size();
        	for (int i = 0; i < size-1; i++) {
        		if (list.get(i+1)-list.get(i) >= 2) {
        			list.add((list.get(i+1)+list.get(i))/2);
        			int temp = arr[list.get(list.size()-1)];
        			arr[list.get(list.size()-1)] = arr[list.get(list.size()-1)-1];
        			arr[list.get(list.size()-1)-1] = temp;
        			
//        			for (int j = 0; j < list.size(); j++) {
//        				pw.print(list.get(j) + " ");
//        			}
//        			pw.println();
//        			pw.println(Arrays.toString(arr));
        			
        			count += 2;
        			if (count >= k) {
        				break hi;
        			}
        		}
        	}
        	Collections.sort(list);
        }
        for (int i = 0; i < arr.length; i++) {
        	pw.print(arr[i] + " ");
        }
        pw.println();
        }
        
        pw.close();
    }
    static class FastScanner {
    	private boolean finished = false;

        private InputStream stream;
        private byte[] buf = new byte[1024];
        private int curChar;
        private int numChars;
        private SpaceCharFilter filter;

        public FastScanner(InputStream stream) {
            this.stream = stream;
        }

        public int read() {
            if (numChars == -1) {
                throw   new InputMismatchException();
            }
            if (curChar >= numChars) {
                curChar = 0;
                try {
                    numChars = stream.read(buf);
                } catch (IOException e) {
                    throw new InputMismatchException();
                }
                if (numChars <= 0) {
                    return -1;
                }
            }
            return buf[curChar++];
        }
        public int peek() {
            if (numChars == -1) {
                return -1;
            }
            if (curChar >= numChars) {
                curChar = 0;
                try {
                    numChars = stream.read(buf);
                } catch (IOException e) {
                    return -1;
                }
                if (numChars <= 0) {
                    return -1;
                }
            }
            return buf[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 long nextLong() {
            int c = read();
            while (isSpaceChar(c)) {
                c = read();
            }
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = read();
            }
            long 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 String nextString() {
            int c = read();
            while (isSpaceChar(c)) {
                c = read();
            }
            StringBuilder res = new StringBuilder();
            do {
                if (Character.isValidCodePoint(c)) {
                    res.appendCodePoint(c);
                }
                c = read();
            } while (!isSpaceChar(c));
            return res.toString();
        }

        public boolean isSpaceChar(int c) {
            if (filter != null) {
                return filter.isSpaceChar(c);
            }
            return isWhitespace(c);
        }

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

        private String readLine0() {
            StringBuilder buf = new StringBuilder();
            int c = read();
            while (c != '\n' && c != -1) {
                if (c != '\r') {
                    buf.appendCodePoint(c);
                }
                c = read();
            }
            return buf.toString();
        }
        public String readLine() {
            String s = readLine0();
            while (s.trim().length() == 0) {
                s = readLine0();
            }
            return s;
        }
        public String readLine(boolean ignoreEmptyLines) {
            if (ignoreEmptyLines) {
                return readLine();
            } else {
                return readLine0();
            }
        }

        public BigInteger readBigInteger() {
            try {
                return new BigInteger(nextString());
            } catch (NumberFormatException e) {
                throw new InputMismatchException();
            }
        }

        public char nextCharacter() {
            int c = read();
            while (isSpaceChar(c)) {
                c = read();
            }
            return (char) c;
        }

        public double nextDouble() {
            int c = read();
            while (isSpaceChar(c)) {
                c = read();
            }
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = read();
            }
            double res = 0;
            while (!isSpaceChar(c) && c != '.') {
                if (c == 'e' || c == 'E') {
                    return res * Math.pow(10, nextInt());
                }
                if (c < '0' || c > '9') {
                    throw new InputMismatchException();
                }
                res *= 10;
                res += c - '0';
                c = read();
            }
            if (c == '.') {
                c = read();
                double m = 1;
                while (!isSpaceChar(c)) {
                    if (c == 'e' || c == 'E') {
                        return res * Math.pow(10, nextInt());
                    }
                    if (c < '0' || c > '9') {
                        throw new InputMismatchException();
                    }
                    m /= 10;
                    res += (c - '0') * m;
                    c = read();
                }
            }
            return res * sgn;
        }

        public boolean isExhausted() {
            int value;
            while (isSpaceChar(value = peek()) && value != -1) {
                read();
            }
            return value == -1;
        }
    public String next() {
            return nextString();
        }

        public SpaceCharFilter getFilter() {
            return filter;
        }

        public void setFilter(SpaceCharFilter filter) {
            this.filter = filter;
        }

        public interface SpaceCharFilter {
            public boolean isSpaceChar(int ch);
        }
        public int[] nextIntArray(int n){
            int[] array=new int[n];
            for(int i=0;i<n;++i)array[i]=nextInt();
            return array;
        }
        public int[] nextSortedIntArray(int n){
            int array[]=nextIntArray(n);
            PriorityQueue<Integer> pq = new PriorityQueue<Integer>();
            for(int i = 0; i < n; i++){
                pq.add(array[i]);
            }
            int[] out = new int[n];
            for(int i = 0; i < n; i++){
                out[i] = pq.poll();
            }
            return out;
        }
        public int[] nextSumIntArray(int n){
            int[] array=new int[n];
            array[0]=nextInt();
            for(int i=1;i<n;++i)array[i]=array[i-1]+nextInt();
            return array;
        }
        public ArrayList<Integer>[] nextGraph(int n, int m){
            ArrayList<Integer>[] adj = new ArrayList[n];
            for(int i = 0; i < n; i++){
                adj[i] = new ArrayList<Integer>();
            }
            for(int i = 0; i < m; i++){
                int u = nextInt(); int v = nextInt();
                u--; v--;
                adj[u].add(v); adj[v].add(u);
            }
            return adj;
        }
        public ArrayList<Integer>[] nextTree(int n){
            return nextGraph(n, n-1);
        }

        public long[] nextLongArray(int n){
            long[] array=new long[n];
            for(int i=0;i<n;++i)array[i]=nextLong();
            return array;
        }
        public long[] nextSumLongArray(int n){
            long[] array=new long[n];
            array[0]=nextInt();
            for(int i=1;i<n;++i)array[i]=array[i-1]+nextInt();
            return array;
        }
        public long[] nextSortedLongArray(int n){
            long array[]=nextLongArray(n);
            Arrays.sort(array);
            return array;
        }
    }
	static void shuffle(int[] a) {
		Random get = new Random();
		for (int i = 0; i < a.length; i++) {
			int r = get.nextInt(a.length);
			int temp = a[i];
			a[i] = a[r];
			a[r] = temp;
		}
	}
	static void shuffle(long[] a) {
		Random get = new Random();
		for (int i = 0; i < a.length; i++) {
			int r = get.nextInt(a.length);
			long temp = a[i];
			a[i] = a[r];
			a[r] = temp;
		}
	}
}