Problem: Polycarp loves not only to take pictures, but also to show his photos to friends. On his personal website he has recently installed a widget that can display n photos with the scroll option. At each moment of time the widget displays exactly one photograph with the option showing the previous/next one. From the first photo, you can switch to the second one or to the n-th one, from the second photo you can switch to the third one or to the first one, etc. Thus, navigation is performed in a cycle.

Polycarp's collection consists of m photo albums, the i-th album contains ai photos. Polycarp wants to choose n photos and put them on a new widget. To make watching the photos interesting to the visitors, he is going to post pictures so that no two photos from one album were neighboring (each photo will have exactly two neighbors, the first photo's neighbors are the second and the n-th one).

Help Polycarp compile a photo gallery. Select n photos from his collection and put them in such order that no two photos from one album went one after the other.

Input

The first line contains two integers n and m (3 ≤ n ≤ 1000, 1 ≤ m ≤ 40), where n is the number of photos on the widget, and m is the number of albums. The second line contains m integers a1, a2, ..., am (1 ≤ ai ≤ 1000), where ai is the number of photos in the i-th album.

Output

Print the single number -1 if there is no solution. Otherwise, print n numbers t1, t2, ..., tn, where ti represents the number of the album of the i-th picture in the widget. The albums are numbered from 1 in the order of their appearance in the input. If there are several solutions, print any of them.

Examples

Input

4 3
1 3 5


Output

3 1 3 2


Input

10 2
5 5


Output

2 1 2 1 2 1 2 1 2 1


Input

10 3
1 10 3


Output

-1

Solution (in JAVA):

Solution:

// Problem : D. Polycarp's Picture Gallery
// Contest : Codeforces - Yandex.Algorithm Open 2011: Qualification 1
// URL : https://codeforces.com/contest/81/problem/D
// Memory Limit : 256 MB
// Time Limit : 2000 ms
// Powered by CP Editor (https://github.com/cpeditor/cpeditor)

import java.io.*;
import java.util.*;
import java.util.stream.*;

public class a implements Runnable{
	
    public static void main(String[] args) {
        new Thread(null, new a(), "process", 1<<26).start();
    }
	public void run() {
		FastReader scan = new FastReader();
        PrintWriter out = new PrintWriter(new OutputStreamWriter(System.out));
		//PrintWriter out = new PrintWriter("file.out");
		Task solver = new Task();
		//int t = scan.nextInt();
		int t = 1;
		for(int i = 1; i <= t; i++) solver.solve(i, scan, out);
		out.close();
	}

	static class Task {
		static final int inf = Integer.MAX_VALUE;

		public void solve(int testNumber, FastReader sc, PrintWriter pw) {
			//CHECK FOR QUICKSORT TLE
			//***********************//
			//CHECK FOR INT OVERFLOW
			//***********************//
			int n = sc.nextInt();
			int m = sc.nextInt();
			tup[] arr = new tup[m];
			int c = 0;
			int freq[] = new int[m];
			for(int i = 0; i < m; i++) {
				arr[i] = new tup(i + 1, sc.nextInt());
				c += arr[i].b;
				freq[i] = arr[i].b;
			}
			if(c < n || m <= 2 && n % 2 == 1) {
				pw.println(-1);
				return;
			}
			Arrays.sort(arr);
			int[] x = new int[n];
			int ptr = 0;
			loop:
			for(int i = 0; i < m; i++) {
				for(int j = 0; j < arr[i].b; j++) {
					if(ptr >= n) {
						break loop;
					}
					x[ptr] = arr[i].a;
					freq[arr[i].a - 1]--;
					ptr += 2;
				}
			}
			ptr = n % 2;
			
			loop2:
			for(int i = m - 1; i >= 0; i--) {
				for(int j = 0; j < arr[i].b; j++) {
					if(ptr >= n) {
						break loop2;
					}
					x[n - ptr - 1] = arr[i].a;
					freq[arr[i].a - 1]--;
					ptr += 2;
				}
			}
			if(x[0] == x[n - 1]) {
				for(int i = 0; i < m; i++) {
					if(x[n - 2] != i + 1 && x[0] != i + 1 && x[i] > 0) {
						x[n - 1] = i + 1;
						break;
					}
					if(i == m - 1) {
						pw.println(-1);
						return;
					}
				}
			}
			for(int i = 1; i < n; i ++) {
				if(x[i] == x[i - 1]) {
					pw.println(-1);
					return;
				}
			}
			
			for(int y : x) {
				pw.print(y+ " ");
			}
		}
	}
	static long binpow(long a, long b, long m) {
		a %= m;
		long res = 1;
		while (b > 0) {
			if ((b & 1) == 1)
				res = res * a % m;
			a = a * a % m;
			b >>= 1;
		}
		return res;
	}
	static void sort(int[] x){
		shuffle(x);
		Arrays.sort(x);
	}
	static void sort(long[] x){
		shuffle(x);
		Arrays.sort(x);
	}
	static class tup implements Comparable<tup>{
		int a, b;
		tup(int a,int b){
			this.a=a;
			this.b=b;
		}
		@Override
		public int compareTo(tup o){
			return Integer.compare(b,o.b);
		}
	}
	static void shuffle(int[] a) {
		Random get = new Random();
		for (int i = 0; i < a.length; i++) {
			int r = get.nextInt(i + 1);
			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(i + 1);
			long temp = a[i];
			a[i] = a[r];
			a[r] = temp;
		}
	}

	static class FastReader {
		BufferedReader br;
		StringTokenizer st;

		public FastReader() {
			br = new BufferedReader(new InputStreamReader(System.in));
		}

		public FastReader(String s) throws FileNotFoundException {
			br = new BufferedReader(new FileReader(new File(s)));
		}

		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;
		}
	}

}