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:
import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.stream.IntStream;
import java.io.PrintWriter;
import java.io.OutputStream;
import java.util.Arrays;
import java.util.Random;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.BufferedOutputStream;
import java.util.StringTokenizer;
import java.io.Writer;
import java.io.BufferedReader;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 *
 * @author An Almost Retired Guy
 */
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 {
        public void solve(int testNumber, InputReader in, OutputWriter out) {
            int n = in.nextInt(), m = in.nextInt(), filled = 0, pos = 0;
            int[] id = IntStream.range(0, m).toArray();
            int[] arr = new int[n], A = in.nextIntArray(m);
            EzIntCustomSort.sort(id, (i, j) -> Integer.compare(A[j], A[i]));
            Arrays.fill(arr, -1);
            for (int color : id)
                while (A[color] > 0 && filled < n) {
                    int rem = n - filled;
                    while (rem > 0) {
                        if (arr[pos] == -1) {
                            if (arr[(pos + 1) % n] != color && arr[(pos + n - 1) % n] != color) {
                                arr[pos] = color;
                                A[color]--;
                                filled++;
                                break;
                            } else rem--;
                        }
                        pos = (pos + 1) % n;
                    }
                    if (rem == 0) break;
                }
            if (filled < n) out.println(-1);
            else {
                for (int c : arr) out.print((c + 1) + " ");
                out.println();
            }
        }

    }

    static class OutputWriter extends PrintWriter {
        public OutputWriter(OutputStream outputStream) {
            super(new BufferedOutputStream(outputStream));
        }

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

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

    }

    static class InputReader {
        BufferedReader br;
        StringTokenizer st;

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

        public String next() {
            while (st == null || !st.hasMoreElements()) {
                st = new StringTokenizer(nextLine());
            }
            return st.nextToken();
        }

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

        public int[] nextIntArray(int n) {
            int[] a = new int[n];
            for (int i = 0; i < n; i++) a[i] = nextInt();
            return a;
        }

        public String nextLine() {
            try {
                return br.readLine();
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
        }

    }

    static final class EzIntCustomSort {
        private static final double HEAPSORT_DEPTH_COEFFICIENT = 2.0;
        private static final Random rnd = new Random();

        private EzIntCustomSort() {
        }

        private static int maxQuickSortDepth(int length) {
            if (length <= 1) {
                return 0;
            }
            int log = Integer.numberOfTrailingZeros(Integer.highestOneBit(length - 1)) + 1;
            return (int) (HEAPSORT_DEPTH_COEFFICIENT * log);
        }

        public static void sort(int[] a, EzIntComparator cmp) {
            quickSort(a, 0, a.length, cmp, 0, maxQuickSortDepth(a.length));
        }

        private static void quickSort(int[] a, int left, int right, EzIntComparator cmp, int depth, int maxDepth) {
            if (right - left <= 1) {
                return;
            }
            if (depth > maxDepth) {
                heapSort(a, left, right - left, cmp);
                return;
            }
            final int pivot = a[left + rnd.nextInt(right - left)];
            int i = left;
            int j = right - 1;
            do {
                while (cmp.compare(a[i], pivot) < 0) i++;
                while (cmp.compare(pivot, a[j]) < 0) j--;
                if (i <= j) {
                    int tmp = a[i];
                    a[i++] = a[j];
                    a[j--] = tmp;
                }
            } while (i <= j);
            quickSort(a, left, j + 1, cmp, depth + 1, maxDepth);
            quickSort(a, i, right, cmp, depth + 1, maxDepth);
        }

        private static void heapSort(int[] a, int offset, int size, EzIntComparator cmp) {
            // If size <= 1, nothing is executed
            for (int i = (size >>> 1) - 1; i >= 0; i--) {
                down(a, i, offset, size, cmp);
            }
            for (int i = size - 1; i > 0; i--) {
                int tmp = a[offset];
                a[offset] = a[offset + i];
                a[offset + i] = tmp;
                down(a, 0, offset, i, cmp);
            }
        }

        private static void down(int[] a, int index, int offset, int size, EzIntComparator cmp) {
            final int element = a[offset + index];
            final int firstLeaf = (size >>> 1);
            while (index < firstLeaf) {
                int largestChild = (index << 1) + 1;
                if (largestChild + 1 < size && cmp.compare(a[offset + largestChild + 1], a[offset + largestChild]) > 0) {
                    largestChild++;
                }
                if (cmp.compare(a[offset + largestChild], element) <= 0) {
                    break;
                }
                a[offset + index] = a[offset + largestChild];
                index = largestChild;
            }
            a[offset + index] = element;
        }

    }

    static interface EzIntComparator {
        int compare(int a, int b);

    }
}